I've been looking for an upgrade to my hifi amp, to which I connect my B2 by optical cable. After a lot of research, the NAD 3020 v2 is the current favourite. It has great reviews, a unique design and a bargain price. NAD's original 3020, first produced in the 1970s, is still seen as a groundbreaking classic.
I'd also been thinking about the very similar, but more expensive, NAD 3045, but don't think I really need the extras it has. I do want to connect a turntable and music streamer as well as the B2, so needed to factor that in: your requirements may be different Brad, but based on the 3020 reviews I don't think you'll be disappointed.
I've never used the B2's internal amplifier, so can't make any comparisons, but I've tried the analogue output (rather than the optical) into my hifi, thus using the B2's internal DAC. I have to say the external DAC is noticeably better.