MkIIs were sometimes only a change of display, eg the 5000 and 6000 in their MkII guise changed from a 7 segment LED display to a dot matrix display, along with revised screen printing on the glass of the latter. Everything else was the same.

The 7000 is an interesting one though, some felt it to be very similar to the 5500, and some felt it to be inferior to the outgoing 6000. One poster did recently express a preference for the 7000 over the 6000, but if you look at the designs, you can see that the 6000 has more in common with the 8000 than the 7000 does (which in itself is closer to the 5500 driver array). I've also read opinion that the 6000 nudges ahead of the 7200, and I personally preferred the 6000 to the two demos I've had of the 7200. It's all subjective though!

The 33 and 3100 have also been rated as pretty much identical in performance by some on here.

Cheers

George