Within weeks of its release, an AOSP-based ROM has already found its way to the Sprint and Verizon variants of the Galaxy Note 2, due to the excellent development work by RootzWiki developer sbrissen. He posted an alpha version of CyanogenMod 10 for each CDMA version of Samsung's secondary flagship phone.
It is quite unusual for AOSP to find its way to TouchWiz-based Samsung devices so soon, especially CDMA devices. For example, the Samsung Fascinate hit Verizon stores on September 9, 2010 and RootzWiki developer jt1134 had a semi-functional vanilla Froyo AOSP build just over four months later (of course, he was an XDA developer at the time ). Apparently the TouchWiz Radio Interface Layer (RIL) became easier to replace over time, since the first AOSP builds for the Verizon Galaxy S 3 appeared just over one month after the device's release (Euroskank's JellyBro, for example).
You might recall in my article from a couple of months ago that developers have found it more difficult to develop for the Exynos chipset than for other leading processors. Couple that with the greater difficulty of porting AOSP to CDMA devices than to GSM devices, and you'll get a better idea for how monumental it was for sbrissen to do it just over 2 weeks after release. Of course, sbrissen said it has proven difficult for him to get AOSP working on the Exynos chipset as well, but he was able to build on the work done on the international version since they both have the Exynos 4412 chipset. He also said he's currently working on CM10.1 but it's not ready for primetime yet.
Of course, now that sbrissen has successfully ported CyanogenMod to the devices, the door has been opened for other AOSP-based ROMs to run on them. Even now, alpha builds Paranoid Android and Pac-Man based on sbrissen's work have found their way to the Sprint variant. Furthermore, Team BAMF member and RootzWiki developer Adrynalyne said there's a remote possibility that BAMF Paradigm could find its way to the Verizon variant (which he owns).
Naturally, there are some bugs (as should be expected on an alpha release), but most of them are relatively minor, such as the orientation sensor taking a little extra time to get working, occasional camera force closes, no streaming music over bluetooth and GPS issues on the Verizon version. In order to flash this ROM, you must have unlocked your bootloader and you must use the unofficial ClockWorkMod recovery posted by imnuts. One other word of caution: once you have unlocked your bootloader, you should not use Odin to flash any other ROMs for fear that you might re-lock or even hard-brick your device.
Since the Galaxy Note 2 features the Exynos 4412 chipset, this CM10 alpha is vulnerable to the exploit published earlier this month. It is recommended that you use Chainfire's workaround to protect your device.