We've been to OX-West 3 times, twice to the old Mormon Lake site and once to Ft Tuthill.
OX-West has by far the largest attendance and vendor participation. The event is getting quite crowded now. But, darn near everything you see or read about online or in print for overlanding will be on display at OX-West. And then some stuff you've never seen or heard of.
If you've never been, the cost of admission is worth it. Attending has become quite expensive in recent years, especially the Overland Experience package. A weekend pass with camping is still a pretty good deal, but, the al la carte features can drive attendance cost up as well.
Sunday Only ticket isn't really worth it as vendors will start packing up in the morning to hit the road/trail. If weather is bad, like last year, expect Sunday to be a non-event as vendors/attendees will get an even earlier start departing.