Beckles-
I just recently did a trip on 'vacations' and highly recommend it. My ticket ended up being booked in H class. I upgraded on the way back from CDG with no problems.
I was shocked when I had initially booked the ticket since it was cheaper at the time to book air through 'vacations' _including_ a hotel than it was with air only on usairways.com!
Regardless, all bonuses, miles, etc worked fine. I too was hesitant. Now I'm sold. I would double check that no additional restrictions have been added since I bought mine.
Oh - one last note. Usairwaysvacations.com is not the same as usairways.com - specifically not allowed to get the online booking bonuses from 'vacations'. Might also be worth a call to the CS desk.