I live in the center of the US and never have problems... Sprint’s back yard!
But I also travel a lot. California has never been a problem. Going east I have had coverage From Missouri, Illinois, Indiana, Ohio, western Pennsylvania, western New York, Tennessee, Georgia, Florida, and western North Carolina. Going north, good coverage in Iowa, Minnesota, western Wisconsin, North Dakota, eastern Wyoming, Colorado, and Kansas. Occasionally there will be a 10-15 mile blank, but those who have Verizon have the same problems.
I have had trouble with NW South Dakota, western Nebraska, Montana. Verizon has better coverage, only because they purchased Alltel which had coverage in those areas. Simply Everything for Sprint is about $50/month cheaper than Verizon or AT&T for comparable services.
Browser?...have you tried Omni 5....it's fast...