Developers, power-users, and anyone else reliant on a virtual terminal/console beware: with FreeBSD 10.0 the KMS drivers will break your ability to VT switch. The console driver currently in use within the freeBSD world doesn't work in conjunction with kernel mode-setting drivers. Once an X.Org Server has started, it's then impossible to switch to the console -- or to even have a console back when closing the X.Org Server -- if using the Intel or AMD Radeon KMS drivers.
The problem has been corrected within FreeBSD HEAD, which is aligned for FreeBSD 11-CURRENT. The problem was fixed by writing a new VT console driver (the "Newcons" project). However, this won't benefit users of FreeBSD 10.0 and can only hope that it will be back-ported to a FreeBSD 10.x point release rather than waiting some years for FreeBSD 11.0.
There's also other shortcomings of the KMS/DRM drivers that were ported from Linux along with the Mesa user-space and X.Org DDX drivers. The console failure details were shared in this mailing list thread while other graphics driver details in the FreeBSD world can be found from their Wiki.
For FreeBSD desktop users dependent upon a decent experience, I continue to recommend NVIDIA graphics hardware with their binary GPU driver as the only real choice for end-users. The DRM/KMS drivers aren't up to scratch yet on FreeBSD and there's no other major GPU vendor offering up official support to BSD users besides NVIDIA.