Have had Boost for about 2-3 years now and I've been enjoying it overall. Like a lot of the others have been mentioning, it is using Sprint coverage, so it's good, depending on one's locations. With me being around the NW FL area, it's solid, but not great in most places. At least now, with there being some expansions of coverage, it's getting better, but for some, might not be enough.
All in all, I'd give Boost a recommendation, but mainly for those who wish to stay local and occasionally travel.
For those that are still in doubt, look up Open Signal to see what's going on in your area for coverage and how strong the signals can be.