Although clrmamepro is great romcenter does just as good a job and it's less confusing. Cmp has some great features that rc doesn't, but quite frankly they aren't needed 95% of the time.
It's personal preference really, but cmp is by no means invaluable.
Oh and the problems about generating your own dat arise from the harddrive games.. something about clrmamepro having to load the entire rom into memory, which chokes the program. I think they take those roms out in the dats, unless they have fixed the problem now.