Bryston 4B St vs newer SST

I would like to have some comparition on those two. I have met with inconsistent opinions, one saying SST is sweeter sounding the other ST sound less agressive with recessed highs (compared to sst). Wich one is to be belived?
I have the 4B-ST, and am currently deciding on whether to get a 4B-SST or 6B-SST, its in a home theatre and I could really use 3 channels. I have a thread languishing without any replies currently, no worries.

I have heard the 4B-SST, I can verify that the SST series is an improvement over the ST. The ST is just the tiniest amount more aggressive with the upper octaves. Both have fantastic bass control, gobs of power, and a surprising amount of detail, especially considering the price. The SST has just a little more resolution and liquidity in the Midrange.

Bottom line they sound very similar with the SST being the better of the two, IMO. I cant say how pleased I am with Brystons customer service. The warranty and resale are a no-brainer. Ultimately, Bryston amps arent the "most" but they offer outstanding performance for the dollar. Besides, that last bit of finesse and resolution is very askew by the "Law of diminishing returns."

If you are anywhere near the Upstate SC, you are welcome to come and hear mine anytime I am available.
I have had the 3b-st with NHT-2.5, 4b-st with NHT 2.9, and 7b-sst with Revel Salons. I found the NHT and ST combos slightly fatiguing when it comes to extended periods of listening (over 6 hours a day). However, I can listen to the salon-sst combo all day (at moderate volumes).

I concur with the above statements about the bass control, detail, etc.. with the st and the sst lines. I cannot make statements about the improvements in detail or other sound attributes between the st and sst because I am comparing apples and oranges due to the differences in the speakers. But the important fact I wanted to add was the fatigue free nature that I observed with the sst line.

My buddy has the 4b-sst with Revel m20 speakers and it sounded increadible.

I have heard the Salons with ML 436 (?) amps and various other speakers with extremely expensive amps. I choose the sst line and have zero desire to change.
I now have the 4B-sst. The 4B-ST is much faster and has more bite to it.
hpilon, are you referring to the SST which is faster and having more bite?

Actually I am also cracking my head on which one to go for. The SST is above my budget wherease a used ST is much cheaper. Do you think I should stretch my budget and go for the SST or settle for the much cheaper ST considering the sound differences?

I am having Sonus Faber Grand Piano (older version) speakers. My current Classe CAP-100 integrated has insufficient power to drive the speakers. Please advice thanks. Personally I'd like to go for the 4B-ST and would appreciate if someone say,"Go ahead it will be fine" although the SST should be better.
I own the sst and auditioned the st against the sst. The sst is smoother and less fatigueing in my book. Because of that I hear more detail and enjoy the music more
I had a 4B-ST in use for mastering applications as well as critical listening and I can tell you without reservation that the SST amps are superior in EVERY category. If you want an amplifier to color the sound in any way, look elsewhere. If you want an amplifier to give you stellar resolution AND pack a wallop without flinching, get a Bryston SST. I am very pleased with my 4B-SST and have no desire to upgrade. The 4B-ST is a great amp. The 4B-SST just takes everything to a higher level.
They are actually very different than I imagined, judging from the posts... To me ST has a bigger lower mid, and seems to be more lively, while the SST is more refined in the highs, and the lows are so extended and tight, low miss aren't as forward but you can def. hear it, and its never muddy. your jaw will drop when you compare the sub output of both. The SST blows it away, and like the person above said, it doesn't flinch. On the ST The lows just sort of build up on the low mid and lows, but the sub range isn't as smooth and easy to hear like the SST. The ST has more bite as everything is very forward, but it isn't refined like the SST. At first, I thought to myself, you should keep the ST, but then I realized that the SST were just being more honest, and the fact that I can hear the sub so well. I decided that I had just reached a new milestone in audio, and I was about to make an immature decision if I kept the ST so I'm keeping the SST and not looking back. 
I was wondering what preamp you guys are using with the 4B-ST or SST. No doubt the amp will make a difference but the preamp is equally important.