As stated, Gladius is correct. FA is for the early models. Later models (Gen III and Gen IV I think) do not have FA.
He is a little out of date on the MSAR E4 (the model that takes AR mags) It has been shipping since the early summer. Plenty of them out there...in fact, I have one. Here's my podcast on my saga of the search for a bullpup.
http://gunreviewpodcast.com/category/long-gun/rifles/
You are being gouged at $1700 for an early model. They are selling down nearer $1100-1200 now. The later models are $1500-1600. E4's are going for $1700-1900. Any more and you aren't looking around hard enough.
Frankly, the best place I've found to learn about them (and other bullpups) is over on the AR15.com forum, Bullpups section
http://www.ar15.com/forums/forum.html?b=6&f=43
The TPD is one of 3 current mainstream manufacturers out there. They haven't shipped many compared to MSAR and Steyr.
MSAR has about 10,000 rifles under their belt. Their early ones had some teething issues...not uncommon for any new product. They seem to have the bugs worked out and have built and excellent reputation for quality, customer service and new product introductions. Given that the company is the firearms division of Microtech blades, they aren't "fly by night" and have some longevity.
The Steyr product seems to be of good quality but they aren't coming out with product intros / improvements quite as fast as MSAR.
I chose the E4.
Positive
- Compact
- Handy
- Less muzzle rise (because of the geometry -- smaller cantilever)
- Longer barrel for same overall length
Negative
- Triggers not as good (long linkage)
- Slow mag changes
- Harder to make ambidexterous (except with the forward / bottom ejectors like the FN2000 or P90)
In general, these rifles do have some advantages, especially for CQB. They will not, however, make me give up conventional configurations.