I once had a Hafler DH110 preamp and DH220 power amp setup. It was better than the Japanese receiver stuff of that time period. It took me several days to fix an intermittent problem. Bad solder joint. Build quality very mediocre. I got a new B&K Pro10-MC preamp and B&K ST-202+ power amp and they were a definite step above in build quality and sound quality. Never had a bit of trouble in over 10 years of use and they are sitting in their factory boxes in excellent cosmetic condition since 2002. They were replaced by Conrad-Johnson EV-1, PV-14L and MF-2250 combination in 2001/2002. Again, build quality went up as well as sound quality. You would expect that for 3X the cost. Never a repair with any of the C-J stuff, except for a few tubes being replaced in the EV-1 phono amp. The preamp still uses the original NOS Mullard M8080 tubes that shipped with the preamp in 2001. They should last at least 20,000 hours of use, as they were rated at 10,000 hours under military conditions in portable field radios.
C-J solid state amplifiers are incredible values in the used market. Their tube gear gets all the glory, but they developed solid state gear in the same league and considerably above Adcom, Bryston, Hafler and B&K gear. An old C-J PFR would be a good solid state unit, or the PF2 if looking at a lower priced unit. An MF-2250 or MF-2500 power amp, or even one of the older amps.
If looking at those other four brands I mentioned, the Bryston would probably be more common in Canada and the B&K more common in the USA. I would pick either one over the Adcom or Hafler units. They were all popular in the 80's and 90's and should be available at dirt cheap prices. Just be aware they will need electrolytic cap replacements to be reliable.
C-J uses bipolar outputs in the MF-2250, and they are better than the Mosfet outputs in the Hafler and B&K amps I have owned. Bipolars have better current drive and are more stable at high temperatures. The polystyrene capacitors used everywhere in the C-J amps give much more clarity than the cheaper capacitors used in the "bang for the buck" brands.
C-J made the Sonographe amp line for some time, and were the same circuitry as the C-J standard line except they used lower cost components. I have never seen or heard an example, however.
I will take my C-J amps to the grave. I have never heard anything else that would make me want to change. I use VMPS Ribbon Monitor loudspeakers.
Dick Olsher has also recommended used Conrad-Johnson solid state as an incredible bargain. People just automatically want their tube stuff, so their solid state stuff never got the attention it deserves. I'll never go back to the "standard" brands like B&K or Hafler.