Hello Hallcon and Geno,
Glad to see others' interest in some vintage SS gear in addition to Decware. I, too, enjoy both.
I haven't heard the small wattage Sansui gear but everything I've read says they are very sweet sounding and somewhat tubelike. I was recently stationed in Japan and looked for Sansui but didn't find what I was looking for in the right condition.
I did find a Pioneer Exclusive M4 (50 watt pure class A) that was only available in Japan. Most similar Pioneer released to USA was their highly acclaimed M-22. The M4 is quite a step above, being in a Brazilian Rosewood case with large VU's and 50W instead of 30. The M4 sounds fantastic and works wonderfully with my CSP2+.
I also found an Accuphase E-303, which is a 130 watt MOSFET integrated. The phono and preamp is excellent. This is biased to stay in class A for at least the first 10 watts. Again, highly recommended.
I also picked up a Luxman LV-105, which is 70w MOSFET with tube gain stage. This is probably considered the best from Luxman's lesser desirable period of the 80's. Again, sounds great and has well respected phono.
Lastly, I picked up a Kenwood KA-7050R which is 105w MOSFET. I alternate this and the Luxman for my stereo HT setup. Either would be more than good enough for most as main stereo, but neither are up to the Pioneer or Accuphase. Keep in mind though that the M4 and E-303 are considered absolute top-tier for their timeframe.
Lastly, I also have a MAC 1900. As I am still in transition from Japan to permanent duty station, I need to play with this some more before I can say much. I enjoyed it when I had it hooked up, but did no A/B. Also, volume knob is a weakness on this model: scratchy, channel imbalance at low volume, serves as on/ off switch so prone to wearing out.
If you have specific questions about any gear I've mentioned, please ask. From my experience, most vintage (70's) Japanese gear was quality. Most brands had premier lines or models that are worth looking for. Differences tend to be better circuit boards (glass epoxy), transformers, noise isolation for pre, etc...
http://www.thevintageknob.org is an excellent resource for general recommendations, specs, and internal pics.
Thanks, Jon.