The bigger the better imo. If 10 footers were more available, I would probably prefer those.
There is a place I go to that has 9, 8 and 7 foot tables. If I have my choice, I will go to 9 foot tables, no question about it.
However if all of the 9 foots are taken, I will play on 7 footers. I feel that 8 foot tables are small enough that the shots are all pretty easy, but not large enough to be too congested, which makes them too easy. At least 7 foot tables get very congested which forces me to play pin point position.