I wouldn't be spooked, I went with the Archon 100 solely based on the deal I got on it, I was originally in the market for the Archon 50 and my biggest concern was the volume difference between the two. Being that I was coming from Mesa amps, it was a semi scary decision for me as my Mesa amps were LOUD. I can vouch for the fact that the Archon 100 can easily be played at bedroom volume at either 100w or 50w. What concerns do you have between the two?
Any difference is really very slight, and only when you push the amp. At low volume amps will have much heavier bass and lose some of the mid definition (sound smoother).