I too would go for the MC-7. It offers a very open window on the sound. There is a rightness about it. I have had all three (still have a pair of 7s and a 10). The 8 was a little warmer than the 10 and the 7 is the leanest. I saw a 10 go for 1600 here and then tried to get that for mine...it didn't happen so the prices you are offered are attractive. They are all great preamps and very under rated and under valued.
Peter
Peter