The OBJ format is deceptive. It's pretty quick to write a parser for it, but it has plenty of gotchas, such as only being suitable for static meshes, since it has no support for bones or keyframes. Nor can it store what the X, Y and Z axes actually correspond to it, it's purely up to the exporting application, and a major headache if you're sourcing models from artists that use different 3d modellers.

I started with .OBJ, but more recently switched to a combination of COLLADA (exported from blender) and a custom binary format of my own making (created from the COLLADA file at build time), and I don't regret it for a second.