I worked professionally (daily) with the 60 for over 10 years and then switched to the 4k. I quantize at least 60% of all MIDI tracks with some degree of "swing" on everything. I honestly can't tell a difference in the feature between the 2 units.
On a side note: You can acheive a tight sound and still have a human feel if you quantize different tracks with different "swing" settings. Even if you're going for a straight ahead groove, try putting your bass at say 52, snare at 53 etc....also see what happens to the feel if you set the bass "earlier" in the quantize settings a bit...say a few ticks or so.....then check the same tune with the bass "later" a few ticks....you will find messing with these settings can change the whole feel of your song.....I notice up tempo jazz players are always a tad early, while laid back blues cats are typically late a fraction....another thing I do is quantize the MPC drums 100% and go back in with a real conga or bongos, shaker etc. for that home grown organic feel....