I've had my BAT preamp for almost 4 years now and have never experienced a single glitch. I probably average about 4 hours of listening, everyday, and have yet to even replace any tubes.
As for sound quality, I thought it was a huge step up from my SF-1 Sig., and also bettered the AI M3A I auditoned on the same day, using the same gear (SF Power 2 and BAT CD player (D5-K or whatever the model designation is) feeding Meadowlark Shearwaters and VS VR-4). The AI unit was much warmer and offered that classic tube sound. The BAT was much better extended at the frequency extremes and had that boogie factor AI was completely missing. Both units were very musical so I guess this is where personal taste comes in.
As for Atma-Sphere, can't comment because I only heard it once and I was auditioning speakers so didn't pay as much attention to electronics.
As for sound quality, I thought it was a huge step up from my SF-1 Sig., and also bettered the AI M3A I auditoned on the same day, using the same gear (SF Power 2 and BAT CD player (D5-K or whatever the model designation is) feeding Meadowlark Shearwaters and VS VR-4). The AI unit was much warmer and offered that classic tube sound. The BAT was much better extended at the frequency extremes and had that boogie factor AI was completely missing. Both units were very musical so I guess this is where personal taste comes in.
As for Atma-Sphere, can't comment because I only heard it once and I was auditioning speakers so didn't pay as much attention to electronics.