Agreed they're very different. I'd say the big island has more variety to offer, but like anything, the level of enjoyment is contingent on what you're into. There are lots of other things that are of interest but weren't in your writeup (e.g. going to the observatory, pololu valley, lava tubes), lava and coffee aren't even really the high points. (Well, Lava would be if you are lucky enough to be there when it's flowing, and if it's flowing at a location easy to get to. I've gone there annually to visit my parents since 2010, and not once have I seen lava. My cousin went to see them once a month after I did, and he walked right up to a lava flow.)