Andor is fantastic, but I think it's important to set expectations before going in. Compared to other SW content it's much slower-paced and more restrained/cerebral.
Mandalorian didn't do much for me; too gamey/Marvel-ey/cartooney.
I've heard Andor described as having the same vibe as The Mandalorian's episode "The Convert"; the one about the former Imperial scientist being rehabilitated and living in an apartment block with other former Imperials.
If so, I will like Andor. I really liked "The Convert".
The quality difference between Andor and The Mandalorian is so stark that I don't even think they are comparable. The Convert is a fine episode I guess, but next to Andor it's amateur.
Andor is prestige TV. The Mandolorian feels like a childrens show by comparison.
If you think The Convert was good, please, please watch Andor.
Mandalorian started strong, with cool spaghetti Western vibes, and then ended up devolving into mediocrity too. In my opinion.
Haven't watched Andor yet.