I'm still a very novice cuber; Moyu cubes in the WeiLong V9 vein are my favorite speed cubes at the moment.
I recently acquired a handful of smart cubes. I have a GoCube, a mid-level GAN, and this Moyu WeiLong V10 MagLev Magnetic Core. It spins just as smoothly as a regular Moyu. This one is definitely my favorite of the lot so far.
The design of the WCU app is a tad archaic, but it functions perfectly well, and after a few days' use I haven't had any problems. Great cube, would recommend.