I finished Tales of Graces f over the weekend and although it was good I liked Symphonia and Vesperia better. Graces is the first one in the series that I don't feel like going through again.
Team Destiny games are like that. To be honest, I generally don't play Tales games immediately after beating them, so I always go for a perfect/near-perfect run, insomuch as getting everything I want.
As far as Graces is concerned, it's not the best use of Team Destiny's CC system, but its decent enough. ToDr is about the best one to utilize it, though even that game has its fair share of stupid bosses.
Xillia's not a bad game. Its major issues are its story from Milla's perspective - gaping plot holes can make it difficult to figure out what happened and why. As far as its battle system goes, its almost as good as Vesperia's. There aren't as many Link Artes for the supporting cast as there could be and most of the class lacks the depth and distinctiveness that Vesperia's cast has. Most of them just don't feel quite as fun as Vesperia's characters do, there's some flaws with the battle engine too, and it probably has to do with the game being rushed. Although to be fair, the only aspect of Xillia that feels rush is the latter parts of the story.
Xillia's not a bad effort for the team who brought us Tales of Hearts. It attempts to incorporate a lot of the elements from the previous two teams that made previous Tales games great, but I gotta say, I think Vesperia was better.
Just for background, I've played every Tales game that's ever made it to the US and even some of the Japanese Tales games like ToDr, and ToD2. I've played Phantasia on SNES, PSX and GBA; and I played Symphonia, Eternia, Legendia, Vesperia and Abyss.