I've been to Union several times over the past two years. It's small and located in the back of a strip mall so you need to know where it is at. Their beers are all cask conditioned ales along with several guest taps. Union is located next to the Monon Trial so if you're walking, jogging, or biking the trail you have easy access to Union.
They created a patio, but I haven't been out there yet when the weather was good enough to be out there. You'll have a nice view of Carmel's Palladium arts center. The staff has always been good and certain nights they'll have bands or DJs. I would give it 3.5 out of 4 beers.