New iMacs announced. Great specs (best power for the $ and USB3), but one some gotchas–the biggest is the lack of upgradable RAM on the 21″ iMac. It’s soldered on. That’s right, you buy the iMac configured for a particular memory and that’s it, sucker. 2012 27″ iMac has four slots, or so says Anandtech. 2011 21″ iMac, if you can find it, has upgradable RAM.
Secondly, no optical drive on these guys. So if you need DVD or CD burning/playing on your iMac, you’ll want an external drive such as this or this (plays BluRay). You can still buy one of these Apple external Superdrives, or consider a much cheaper non-Apple optical drive.
Other item of note, but not a dealbreaker, is the lack of firewire ports on these. So far as I can tell the Thunderbolt to Firewire adapter will suffice, though there may be some devices like high-end audio peripherals that don’t work with this adapter. So if you depend on a particular external I recommend research before you upgrade.
More information once I get hands on with one of these things. Not clear exactly what RAM they’ll take yet.