I prefer DL, but both worlds are so big that you can adventure for a lifetime without ever touching on the central plots of either world.
I think DL allows you to use the 4E races more easily without any real changes (except Tieflings).
For Draconian, use Dragonborn.
For Kender, use Halflings.
For Qualinesti & Sylvanesti, use Eladrin.
For Kagonesti, use Elves.
For Irda, use Changelings (99% likely in the MM).
No Gnomes or Half-Orcs. I mean, those Tinker Gnomes were never really a PC race.
5th Age would be a great way to introduce Warlocks. You could play all Martial classes and Wizards during the Age of Despair. Lots of options.
That's what I wanted to do for my next campaign, but I got out-voted.