I think this project is well on its way. It's clear to myself, and hopefully the members of this community, that this project is nowhere near finished and FMI is commited to making XMP as perfect as possible. Sure there are bugs, but I have yet to see a first release of a mod that didn't have some bugs. FMI is very lucky to already have a community at their disposal who will let them know, in no uncertain terms, exactly what is wrong.
As far as the actual game, I think it is great. Most of the bugs don't detract too much from the core gameplay, and it's clear that they took care to make sure that the everything looks the same as the original. IMO, the vehicles are much better than before, and the new maps are great.
I can only speak for myself, but I am certainly impressed at the quality of this release. There really isn't anything that makes it unlplayable, just some tweaks that need to be made to really get XMP cooking. It looks great, and I'm confident that FMI will make sure that it plays great too (not that it doesn't play well already).