Anyone who says that Boost (i.e. Nextel iDEN) "doesn't have coverage in buildings" has no understanding whatsoever of physics, or even basic technology, so don't believe anything they say in this matter, ever.

The overriding parameter is distance from the tower/antenna. In THEORY, 850 MHz signals can penetrate physical barriers better than 1900 MHz signals, but as a practical matter that point of physics is vastly overwhelmed by tower/antenna placement and distance from the antenna to the user's handset.

It sounds like the original poster might also have a handset that is either a poor design (inherently a weak model) or perhaps a broken unit. With my Nextel service the i560 handset was comparatively weak in terms of signal reception, whereas the i55sr and i580 models have better signal.

WRT carriers, they all have areas of great coverage and areas of poor coverage. They all drop calls and garble audio from time to time. It's strictly a matter of the number and placement of antennas in the areas where you need service. If one carrier gives you poor service, use another carrier.

Don't listen to the "Verizon zombies" that will tell you that Verizon has coverage everywhere, because those people are just plain brainwashed. We have a split of Verizon and Nextel in our family, and there is no significant difference in network coverage or quality for us (southern CA), they're both decent but they both have weak areas too.