The playtest for the Warlock class updates has ended, and what seems to be the ultimate revision for the class has been released. Not much has changed from the previous document, but they did succeed in implementing the most demanded fix: Star Pact warlocks can (finally!) have their choice of Charisma or Constitution for their fixed at-will, Dire Radiance. This had been a long standing problem for a build that allegedly allowed focusing on either ability modifier, and goes a long way towards improving the playability of the Star Pact. Aside from that, a few daily powers have received additional rewordings, usually to boost their power (notably, Hunger of Hadar has basically recovered its pre-errata status), and the at-wills Hellish Rebuke and Dire Radiance have been rewritten so as to trigger only once per round, which seems only fair and prevents a few egregious loopholes.
If you have ever been curious about playing a warlock, the class is in better shape than ever, and well worth a shot. It’s still a striker with relatively low damage output (meaning that it’s not uncommon for non-strikers to hit harder than you), but on the other hand it offers very respectable control and many, many tricks. It’s also one of the most supported classes in the game, with tons of options for powers and feats, and even a good deal of class-specific magic items, offering a potential build variety that is only matched by fighters and wizards, if at all. And, most importantly, it’s quite fun to play.
By the way, for those lacking a Player’s Handbook or a DDI subscription, the class is now available for free on wizards website.