I have a couple half-face ones (respirators, that is) from North as well as 3M. Silicone face piece is soft and conforms well, P100 filters can either be the plastic cartridge type or the lighter soft, padded material without the plastic shell. It's important to have one that fits your face. I wear my normal glasses with either of these, no problems.
One thing I would not recommend is a big-box store sealed in a clamshell variety. Lots of places around here seem to be carrying these now for the homeowner, but the cartridges can't be replaced and the face pieces can be really cheap. I'd avoid those unless you need it for just one or two specific projects.
-frank