I prefer VRBO to BnB, but many folks use either one.
VRBO books stand-alone places only. BnB sometimes puts you in a back room along with the owner family.
Sure VRBO works as well.
To the OP: think of the Tucson Gem Show as the superbowl...you will pay accordingly due to the massive influx of dealers, tourists, etc.
If you have not been before, prepare to go into a lot of hotel rooms. Dealers book the more affordable hotels across town in their "area" to show and sell their merchandise.
Great time though.