I would suggest considering the older Krell 400i vs. either the older 300 or the new S300i. But that is based on my preferences in performance. The older 300i was nothing special, with the S300i being a pretty decent improvement over it. But I still feel the S300i falls short of the old 400i, which is better in my opinion all the way around. It (400i) will be a bit smoother, better soundstanging and in my experience a bit more pleasant overall. I like Krell (owned several of their power amps), so I am not saying the old 300i sucks, just that the 400i is notiecably better than it or even the new S300i. The 400 can be bought used pretty cheap, something like $1500 I think.
That being said, I think there are better integrated amps out there than any of these, but you would need to provide more info. for a good recommendation (as requested above).
That being said, I think there are better integrated amps out there than any of these, but you would need to provide more info. for a good recommendation (as requested above).