well, trying to be objective here but I personally think her concerts are nice. She's not the best entertainer as she does not dance really or anything of the sort, but it's always a pleasure to watch her sing and interact with the audience. The production is always on point. This year's tour is really nice, even though I couldn't personally attend this year (so saaaad x_x) but I know fans really enjoyed seeing her in better shape vocally this year.
Since this is a BEST tour, if you like most of her singles, you'll most likely enjoy the concert. I still think Let's Music Tour and perhaps YES MY JOY remain my favorite tours (even though THE ONLY STAR and LIVE IS REAL were fantastic tours, her voice wasn't that great, especially during the dates they picked for the DVDs)
Just don't expect something really fancy (except perhaps the beginning session with Mika doing aerial yoga while singing CANDY GIRL :p), it'll be classy and simple, but beautiful at the same time