Mandalorian was a very fun watch. Don't worry if it feels like a couple episodes in the middle seem to be declining...it finishes on a high and brings everything full circle pretty well. The Clone Wars is the very highly rated animated series...that would probably take much much longer to watch (I'm personally in Season 2; and there's a list of the order in which you should watch those episodes just like there is for the movies but it's mostly just going in order with a couple detours here and there).
I haven't really used Disney+ for much more than that yet. It makes sense if you just want to punch it out during the quarantine, but if you wanted to wait and get the better bang for your buck, they'll eventually have the new Marvel stuff coming/you could always wait until Mandalorian Season 2 and just run through both seasons at once.