yeah Abyss is a great game as well and manages to have two great fighters that I would actively switch between. I never really got into Phantasia either mostly because it was the first one on SNES and the fighting system was rather meh.
Eh honestly, Tales of Symphonia was the only main one I've really got into and beaten. I got Tales of Phantasia, but it was the GBA edition and I dunno...it just seemed clunky and unpolished next to it. And since I was a Nintendo kid while growing up, never played much of the other ones (though I still kept up by reading like guides on them lol). If you have any old ones to recommend I'd like to hear it though!
I also have Tales of the Abyss for 3DS, but I haven't even played it yet since I'm so backlogged in 3DS games at the moment.
Symphonia 2 mostly focus' on the two new characters, the original cast is always 'guest characters' who cannot even level up. To get the best ending (not that Emil even deserves it) you have to do some nonsensical things like not pledge to Lloyd at the start, and a monster in Triet, and not getting hit in the Lightning Temple too many times. The last two boss battles for the normal and good ending don't even matter as well. You have to go in knowing that it's not nearly as good as the first on any way and not even made by the same devs.
Symphonia 2 is easily the worst of all the Tales games, two human characters that can actually level up, most of the monsters end up being OP that you can't even control. There is no overworld. They recycle the hell out of some places. It's bad don't waste too much time and money getting it.