With the same proviso, no such thing as best, I suspect the Vac Phi beta would be best in most circumstaces. Meaning it's output of 110 watts I believe, would drive most speakers. Having had a few very good integrated amps, Lavardin IT, Karan K180, clearly the best in my system was the Viva Solista. At 22watts, clearly, it won't be best in many systems.
Others I might mention, the newish Pass labs 150 integrated and Conrad johnson C200. Not much experience of them, but the companies products are always good, in my view