I got this wobble board for my birthday to help improve my balance and lower core muscles for a couple of sports/activities I thought it would benefit. At first I couldn't go a full second on the pivot, but in only a few days of occasional use (it was probably more time between sessions than actual use that mattered) I became good enough to stay up 10s+. This board has a threaded pivot that can be turned to increase/decrease the pivot height, so it'll be interesting to see how much difficulty that causes.
The board is smaller than I had expected, but it's really not a big deal--appropriate size for standing on two feet. My one complaint is that there are occasional loud creaks that I assume are happening with the threads/base. This is one of those "little things" that might stop me from using it, because I'd rather not disturb the downstairs neighbors. I'll report back if I can pinpoint the cause; if it is truly the board and not my floor, stay at 4 stars.