First of all it’s important to make the distinction between RekordBox and RekordBox DJ. The first being collection management software primarily used for prepping your collection, playlists and sets for use on RB compatible Pioneer (club) gear.
The second is a DJ software package, same as Serato, Traktor, Cross, VDJ and others. As stated, still in it’s infancy. Promising of course, not in the least because it’s got Pioneer behind it. But many things not implemented (yet), not in the least the option of using other than Pioneer controllers, although this should arrive within the next year.
I have to admit that while I played around a bit with the export function in Cross (been a Mixvibes user for some years now) with RB 3.0 and that integration worked well, I have not spent much time with that feature in 4.0. In how far the proper working was a result of Mixvibes being the makers of RB 3.0 I don’t know. With RB 4.0 it’s all Pioneer and I doubt they will open their doors to let other developers in.
RekordBox 4.x has pretty good integration with iTunes. So if, as advised here on more than one occasion, you use iTunes for collection management, it’s pretty easy to prepare a RB stick for use on club gear. Obviously RB does it’s own beat gridding, so no help there no matter what management software you use. Same goes for cue points. Again, this worked reasonably well in Cross with RB 3.x, but since I don’t use that feature much anymore I never checked with 4.x
Apparently the next implementation of RekordBuddy is able to do a lot of the things that DJs would like to see for cross-platform data-exchange (i.e. letting you export cue points from one software to the next). No idea how effective and easy to use that will be.
When you look at RB DJ, the DJ software, it all boils back down to my preferred selection method for software and gear, which starts with your workflow. That is what should dictate which software is best for YOU.
All in all, there is no cut and dried answer I think. I keep an eye on RB DJ, but I am happy with Cross for the moment. For the few times they make me use club gear (ever decreasing occurrence) instead of letting me use my laptop (USB HID with Nexus players still beats RB sticks imho) and/or my controller, I’ll just make a set with RB from my iTunes collection on a USB-stick. I don’t worry too much about cue points. I know my core collection well enough to know where most interesting points are and I don’t rely too heavily on cue points for my gigs. So only a minor inconvenience not having them.