In previous, similar threads a few people have said that they found M60s to be clearly better than 603s. The 50s should have a very slightly recessed midrange relative to 60s but otherwise fairly similar.

My guess is that most people would prefer 50s to 603s but I have not seen any direct comparison to confirm that.

Between 60s and 703s it seems that a small majority prefers the 60s over the 703s (vs. a slam-dunk win for M60s over 603s).

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8