I've played the Dark Spire. I absolutely love it. But it would be a tough one to recommend to someone unless they know exactly what they're getting themselves into.

Watch some video or something and see if it's something you would be into. It is intentionally VERY retro, so it's best appreciated if you have some experience with the older games in the genre. If not, that's fine- it's a great game on its own. But just be prepared that a lot of things are confusing and hidden and not well explained, somewhat on purpose. The game is also very difficult, again, on purpose.

That being said, if the visuals are something you can appreciate (it even has the option to play the entire game in wire-frame mode like the REAL retro games in the genre), and you don't mind some trial and error, it's a lot of fun.

Etrian Odyssey is often said to be somewhat a love letter to the old retro blobbers, because it's difficult and you have to draw your own map and it involves a lot of experimentation with team strategy. The Dark Spire is REALLY a love letter to them, probably more than it ought to be.