If you do a buddy-check (part of the system) neither should there be between to padi-divers (or whatever recagency you choose)DIR isn't an agency so we'll focus on GUE, the most well known of the DIR advocating agencies. The thing about DIR is consistency. Two 100% DIR divers who've never met before should know 99% of what their new buddy has equiped, where it is and what to expect. There should be no suprises.
A brand new diver (earlier this year GUE was considering offering an OW course but it hasn't gone truely public, if it ever will) can enroll in the DIR-F course. There is no dive requirement listed on the website other than holding an OW certification...snip...
but ow+ dirf = more training and more time with an instructor than just OW so how can you compare the two? If other agencies started requiring ow before you could take ow then we´d have a fair comparisson...apples and oranges...