I've had minimal issues getting FCP XML's in and out of resolve 8 & 9. It's pretty robust in my point of view. If its a really crazy timeline (pip, insane layering, variable spd fx). I just export a media managed project, import XML, and render with source file names and reconnect from my project. Easy peasy lemon squeesy.
Of course this is from someone who had to deal with final touch back in the day...
Joseph Mastantuono
http://www.goodpost.net
Color Grading & Post Production Consulting