Personally I prefer Top spin series to Virtua tennis. I had Virtua tennis 3 and it was too arcady for me and you would get into unrealistically long rallies all the time. Dont know about Virtua tennis 4 though. Top spin seems a bit more realistic for me.
Reviews from IGN on both latest instalments (Top spin 4 is newer) However Virtua tennis 4 is on the cards, due for release summer 2011 and will use play station move
Top Spin = good. But get Top Spin 3, its like a fiver and pretty much the same as Top Spin 4. Unless you need the most up to date version then just go for Top Spin 4.