I actually liked Guardian's Crusade (Knight and Baby...lol!) back in the day. I played it to completion and enjoyed my time with it for what it was worth. It's a traditional turn based RPG through and through. You collect "toys" which are sort of clockwork-like windup robots in nature and they act as familiars/spells in battle. The little dragon (or baby creature) that accompanies you can perform in battle, but it's essentially a solo game, sort of like Tsugunai: Atonement for the PS2, if you've ever played it. I couldn't tell you a thing about the story/narrative, but I recall the game feeling relatively lighthearted, but it's got that early 3D PSone game aesthetic/charm which is cool. Can't remember a damn thing about the OST though, hah! Game's got an interesting world map with a decent amount of secrets/side areas and an optional boss or two if I remember correctly.
I mean, you could do worse with RPGs on PSone. I'd like to think of it as a very innocent title. Does nothing particularly wrong nor does it really do anything special, doesn't try to be something it isn't, etc. Definitely cheap on eBay too.