Mario Tennis is one series I've somehow managed to avoid, and I think a lot of that is just because Tennis never really interested me a whole lot in the first place. I'm not even sure I've tried any of the Mario Tennis games. I looked up a video of Aces though and it looks pretty well polished and like it'll be fun. Might give it a try if someone has it, but have no plans on picking it up myself for now.
About the only close thing I've played to a Tennis video game is Super Tennis for the SNES, which I still own and my sis and I still quote the announcer to this day quite regularly.