I DM a version of 4e that uses PHB1, PHB2, MP1, AP, DP, PrP, AV and AV2 for player character stuff, plus perhaps a smattering of other books. I have the odd house rule or fix. I'll use the Essential's era monsters quite cheerfully along with the older ones, though I won't run the Essential's characters or allow the options.
The main large group I'm DM'ing for (can be 6 to 8 PC's with the odd Companion now and again) largely seem to like it. (I'm the second person to run it for them; I was originally a player - I miss my odd Elf Fighter). They're about to finish or be finished by Gardmore Abbey, which slotted very well into the flow of the campaign we're playing and it was so worth the money. I'm hoping this game will and run.
Some of these players also played in a short arc I ran elsewhere; that was my first go at running 4e, though I've ran many a game before over the years.
I use the same homebrew/Loot Freely game world for a two player game, too.
I keep wishing I could play my own game. I could probably stand to run another game now and again.
Prior to all of this and that, in the early days of 4e, I played a couple of characters under another DM that also had the same players from the aforementioned 2 PC game in it - I still miss playing that cleric. (That DM is running the splendid The One Ring RPG these days, which in my view is mostly excellent and I'm picky about my Tolkien.)
I still play on the somewhat rules open play-by-post forum here, with Essentials add-ons and all.
I'm fond of the game, certainly. Would like to play again in person, too (though, yes I'm not bothered about Essentials PCs).