Good thing you made this thread indeed, and I gotta thank this place because it was what introduced me to Trails series (back when the site wasn't even called cdromance or RGT), I found Trails in the Sky around the time I started playing PSP games and this site was my go-to place and since them Trails has been one of my favorite JRPGs, it wasn't long till I found Ys too.
I'm a bit saturated from Trails games right now because I played it a bit too much in the past years so I'm waiting for the Sky Remake to release so I can reignite my love for this franchise and play some of the recent games (Kuro/Daybreak).
I haven't dedicated as much time for Ys and I did for Trails so I won't talk about Ys.
So what can I say about Trails franchise as a whole?
It's a JRPG on it's roots, it has a great story with great worldbuilding, it may be a bit cliche or a bit cringy with it's anime troupes, it may have a bit of fanservice (on cold steel games onwards) and some flaws but the franchise is great. I recommend every JRPG fan to venture into it.
The OST of the games are one of my favorites too.
If I had to criticize something is that they often take too long to localize their games to the west.
Also, I really would like to recommend a youtube channel called
The Kiseki Nut, he's a cool guy that talks about Falcom games and many other JRPGs. He also have dedicated videos explaining the story or many parts of the game that people may find confusing or difficult to follow so it's worth to check it out.