I concur with George about timing.

The G61 came in a few years behind the G68 variants - it had no MRC so functionally was somewhere between the 568.2MM and the G68J - the G68J was basically a stripped out G68xxx and come out slightly later than the other G68 models - no tuner, no/limited zones, limited audio configurations available. Apparently the J was for 'Japanese'/Asian market but it became quite popular with DSP owners who didn't need all the extras for the G68D. It basically was the G61R, albeit in G68 sized box.

When V2 of G68 came in, M introduced the G68r and I think the G68J was phased out at the time as otherwise I they would have been identical apart from case size. The V2 G68's introduced the USB audio input and hence this appeared in the G61r too. So a G61r will have the USB audio input along with the later G68's. For much the same reasons that you don't see many G61r's, you don't see that many G68's with USB audio input.

Personally I prefer the smaller form factor of the G61r.[typo corrected]

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).