Yah everything said above is correct. 2200+ and below are T-bred A's, don't expect T-bred B's in those models anytime soon though, they are still having problems filling their supply of 2400+ and greater CPUs.
As for T-bred A vs. late stepping Pal's, it really depends on your cooling solution. People have reported insane temps with their T-bred A's at the same speeds they got with their AGOIA pals, @ 1.8ghz. I have a 1700+ T-bred A, but also have a very nice Copper HSF (Alpha Pal8045) and an 80mm fan on it, so it actually runs much cooler than my 1800+ Pal at a higher clockspeed. It probably has to do with the much smaller die size on the T-breds, but you can expect to achieve around 1.8ghz with both. Only other consideration is that the T-bred A's don't have the laser cut pits in them, which makes changing the multiplier much easier.
Chiz