First, let me point out that DnD usage has now outstripped D&D. DnD 5e gets 5.98 million hits on Google, while D&D 5e gets only 2.66 million. Blame Wizards of the Coast, as they spell it that way too at http://dnd.wizards.com/.
We just moved to the official 5e rules, from the most recent playtested rules. Things changed! Bards got weaker, and the Spy background disappeared (for now), which was a pain because my character was using it. I’m sure Spy will show up again in some supplement though. All of the characters changed from three proficiencies to two, but tool proficiencies got added in as well. Search disappeared as a skill (I guess it is all just Perception now). Clerics can rock out with the Sacred Flame cantrip these days (1d8 damage, endlessly cast!). Several of the DnD creature types have disappeared, including Deathless, Magical Beast, Outsider, Shapechanger, and Vermin. Hilariously, the new list is exactly the same as used by Pathfinder, except that Monstrous Humanoids have been changed to Monstrosities and that Vermin has been dropped by DnD! The 4th edition creature types have been completely ignored by 5e.
Oh, and it takes 300 XP to move to second level now. “Back in my day, it was at least 1500 XP!” says my 1st edition character, who then points to the cartoon to the left (which came from WrathofZombie’s Blog). “Are you kids so pampered that even leveling is that much easier?” Anyways, these are just a few of my thoughts after my first day of playing the new Player’s Handbook 5e. There’s a lot more data at Reddit, if you’re interested.