I've lived in the Twin Cities for over 20 years now. You have to remember that the Twins were in the Metrodome prior to their current stadium, so compared to that, Target Field is a huge improvement. That being said, it's ... fine.
It's a big ol' pain to get in and out of, but so are a lot of ballparks. Even if you take light rail (which, btw, isn't necessarily significantly cheaper if you've got a group of at least 4), the crowd after the game can have you there waiting for 45 minutes to an hour just to get on your train which will have you packed like sardines. It's supposed to be less hassle than parking nearby, which has you negotiating a pretty bad traffic situation in the downtown area, even if you know which streets you're supposed to take to get where you're headed (I haven't been in downtown Mpls lately, but I assume it's construction season, too). Both options kinda suck. If you have a group of 4, I say drive to the ramps nearby.
Stadium itself is nice, and does have nice food options (at expected stadium-premium pricing). It's just a regular urban ballpark, IMO. Nice enough.