“wigswest” - sorry for the late response.
One way to view the difference between these two practices is suggested by the Buddhist distinction between samatha and vipassana. You’ll find a very nice summation of some of the controversy surrounding this distinction at
http://www.youtube.com/watch?v=TSVQhhEt7tQ
To encapsulate the discussion there-in: based on the classical definition, samatha leads to eradication of emotional defilement - that is, towards clarity of mind. Vipassana leads to the ending of ignorance (“cognitive defilement”) - that is, towards clarity of discernment.
Mantra meditation is generally proposed as a method of purification (ending emotional defilement). I would guess that your breath meditation was likely proposed as a method of gaining insight (ending cognitive defilement).
These are two different aspects of liberation, with neither being dispensable. Any kind of developed meditation methodology will suggest methods to attain both clarity of mind and clarity of discernment.
Mantra is common in some buddhist meditation traditions, like tantra. Mantra is an important introductory method to attain shamatha. Vipassana occurs in silence, without cognition. Furthermore, mantras are not nominal designations, and thus are not a cognitive object. They are like breath; when you breath there is sound there is feeling. Mantra is very much the same. I’m training in the Drikung Kagyu lineage of Tibetan Buddhism and we describe our practice as yoga. I’ve been around the bend a few times with the differences in view of buddhist vs non-buddhist yoga, and basically the differences in descriptions are not important. Om, Om Ah Hung, Ayam, Ah, whatever are no impediment and are helpful
One thing I would caution, and I do think this is important, and Yogani may disagree, is that you shouldn’t see kundalini as sexual bliss. In fact, the kundalini as it enters the central channel involve more winds than just sexual. The bliss experience from kundalini is a means to gain non-cognitive awareness in deep meditation. I see people getting sidetracked with sexual interests, thinking tantra is sexual. There’s nothing wrong with good sex, it’s just that good sex and good meditation are not related.
The buddha’s command of non-clinging to views and non-attachment to desire is very important, and is the path to enlightenment. The best meditation is the one where you are awake; remember that. Best,
TMS
So much has been said here! I want to comment on it all. I took a break from the mantra in December because it was just not working for me. I found no matter how much I self paced I was still irritable a lot of the time. I felt very much on the outside looking in with regard to the rest of you. I didn’t have a lot of inner silence, even started to wonder what the heck everyone was talking about. I had some ecstatic conductivity but it came and went and I felt frustrated because nothing stablized. I just didn’t feel like I was getting it. Oh, and I practiced consistently with AYP for almost 2 years.
I never used the breath as object until recently because it made me overly self conscious. I was sure I wasn’t doing it right. Anxiety is a big problem for me altogether. But when I was younger, I had experienced samadhi states consistently each time I sat for a couple of years. I had stumbled upon them on my own and had no context for understanding them. I stopped meditating when I was too happy and too alone! 
Then when the internet came along I was able to find fellow seekers. 
I became prepared to have a go at it again. It has not come easy and I still can’t find my way back to my previous success, though I have had some lovely moments. One of the most notable things I had realised back then was first, the suspension of the breath and second, the suspension of discursive thoughts. Which to me led to all the other delightful things I learned. When coming to AYP and finding that a mantra, which is words, was the method, I felt that same as YIL ‘feels a bit “artificial” (still can’t shake this feeling!)’ For me it always feels like going backward. The feeling of being free of words is most wonderful and I still would love to be able to go there at will. I would love to hear if anyone can resolve this dilemma.
Using the breath lately has helped me to discover one thing consistently. When I get off the breath a little image in my mind’s eye pops up. If I just note it, not push it away as an invader, but give it just a little nod, a pleasant feeling arises. After a series of these I feel better when I get up from meditation. Once again I feel I must not be doing it right but feeling bad most of the time isn’t either, right?
So reading all your rah rah posts makes me want to try the mantra again. Maybe I will.
Love to all,
Jill
Hi Jill,
Thank you very much for the lovely post. Reagrding this maybe this other recent topic I started may help you as well:
http://www.aypsite.org/forum/topic.asp?TOPIC_ID=5244
Yes, I understand what you mean about the mantra. How can a repetition of some syllables bring the mind to rest? Well, maybe it is one of those paradoxes. There are many mysteries in life 
I still cannot understand it and I wish I did (because I would be more clear and motivated about it, even to explain it to other people) but I guess it will come in time as I keep opening. For now I keep trusting all the people here that are more advanced in that this is a good tool. It is doing something for me that is true!
It is all about going back to the heart and, if they say a mantra will help do that, who am I to disagree? Let’s find out! And, in the process, I have hope that this question as well will be illuminated in the process…
There is another type of meditation you can try if you feel the mantra meditation (or breath meditation) does not work for you.
(http://www.aypsite.org/forum/topic.asp?TOPIC_ID=5249
Namaste, and hello to all. I’m new to this site; I found this post while doing a search: yoga+breath+meditation+mantra. The reason for this is due diligence, finding out what others are doing in this area, because I am hoping to found the Hansa Yoga Meditation Society in the United States. Your discussion is particularly interesting to me for what has not been said, or barely touched on: the soaham sadhana.
With all the comparisons and contrasts in your discussions here, I want to share an alternative view. I have been practicing a number of powerful and effective meditation techniques for over 35 years, and I have gradually learned a very deep certainty: breath WITH mantra, synchronized together, can bring even greater pranayama benefit than either technique practiced singly.
There is a booklet called HANSA YOGA: The Elixir of Self Realization, by Pandit Shriram Sharma Acharya, available on-line for about $6. He writes, “The scriptures of spiritual sadhanas have mentioned so much about the hamsa yoga that if compiled collectively, these descriptions would appear like an independent branch of the yoga sastras.”
In other words, the practice of the soaham sadhana has been distilled out of numerous styles of yoga, and dubbed Hansa Yoga, in order to emphasize breath-mantra-meditation as a very important, powerful, and fundamental method which should not be marginalized among a plethora of other approaches and techniques.
I found several Himalayan Yoga web sites with info on the use of the breath mantra, Hansa/Sah-Han, So-Hum and similar variations:
http://www.yogajournal.com/practice/504
http://www.swamij.com/sohum-mantra-108.htm
Someone spoke of using “I am” as a mantra? if you’re looking for some profound meaning behind the mantra sound, Sah-Han-Sah-Han-Sa… translates to “I am that I am that I am…” (according to one of the web sites linked above). But entering a deep meditation state is a pure form of mysticism, finding stillness and mental silences between waves of thought, beyond meanings. The breath mantra is already built into our consciousness, anyway, so we may as well take advantage of it.
Everyone forms their own opinions and question what may work better or not so well, but I promise you this very focused method is IT. If you’d like more detailed instructions on how this is done, email me and I’ll get back to you. realmystic@live.com
NAMASTE, PEACE & BLESSINGS, Yogi da