Solid, veteran company that has been around since the beginning of action RPGs. It's great that they managed to survive this long and remained largely true to their roots. Rare story.
I've beaten Ys 1 & 2 Turbo CD, 3 Genesis, both 4s (Dawn of Ys and Mask of the Sun are not two different versions of one game, they are two different games), 5, 6 PC and 7. I liked all of them originally except 7, especially 4 I'd say. In retrospect, I was probably wrong about 7 - the change in gameplay style was probably a good thing, and hopefully I'll play 8 and 9 some day. I've heard 8 is incredible.
Xanadu Next is dope too. Trails of Nayuta is very dope and yall should play it on PSP. One of their best games. I beat Trails of Sky, didn't like it. Very bland and wordy. Legend of Heroes 1 on Turbo CD was solid. I played the Legend of Heroes PSP trilogy (III-IV-V) but the horrible localizations ruined them so I don't know if they're legit or not, honestly.
In summary, great company, especially when it comes to action RPGs. I'm really interested in Tokyo Xanadu, it looks cool.