Name one that loads quickly and is widely supported.
FBX loads very quickly, and comes with a full SDK. That makes it easier for you, because if the file format gets an addition so does the SDK, and you just have to recompile if you want to takes advantage of the change.
I don't particularily like Collada, in fact I agree that it is a bloated format, but that is besides the point. It is supported in max, maya, xsi, blender, milkshape, etc. which means you don't have to do anything but write a decent loader for it.
Of course you might need to convert your files to an internal format, but that's as simple as writing a chunk of memory to a file, if you just want your own engine to load it. It still saves you from writing an exporter for software X, Y, and Z. So you end up needing to do 2 or 3 things, instead of writing/buying and supporting exporters for a number of different modelling/animation packages.
I don't see writing an exporter for Unwrap3D (although it's a great piece of software) will help you or at least not the users of your engine.