I only started with Tales of Symphonia first, because it was the first one that came out here. But I'm not complaining, I love it!
I've played Phantasia, Eternia, Symphonia, Vesperia, Hearts, and Symphonia 2. I also have Tales of Destiny (original) and the Abyss (Japanese copies), but stupid region-lockout has prevented me from playing it. One of these days, I'll get around to getting rid of that.
There's nothing I truly dislike about them. I've somehow managed to get very attached to them. Of course this excludes Symphonia 2, as I recommend even the biggest of Symphonia fans to stay away from it.