Cex = Retail that you buy in store
Dex = Debug - Developers Console that costs thousands of dollars
But recently we were able to convert CEX > DEX by modifying the Flash. With it you can play any 4.21 game from original disc, you can play any 3.70+ game backup that has an update from a specially formatted hard drive
Benefits of a DEBUG TEST console:
.- Run Homebrew and ANY eboot signed FSELF with the SDK in ANY debug fw until the last one 4.11.
.- Execute the last 3.6+ legit games in disk (even in 4.11) You can run homebrew and new games but with original disks NO BACKUPS because the eboots have to be signed again as FSELF.
.- You can use EVERY single option from SDK (Debug, Development, etc)
.- Execute backups max 3.55 using PS3gen or using debug pkgs and eboots FSELF 0x8000 (re-signed with the psn_package_npdrm, any package preparing them *geohot* type).
.- Direct downgrade from 3.6+ to 3.55 with ONE pup fast way to do it.
.- improves and many things from the latest FW (Support of new devices, etc).
.- For the moment nothing complicated to fix, you have no BD or DVD playback because you can't do it on DEX but in 3.55 dex this is can be fixed (Easy way) in any 3.6+ you need certain check.
1) What do you mean retail functionality? You can restore dvd playback and ps store to name a few by some sprx copying and xml editing. Just unpack a dex fw for 3.55 and a cex fw for 3.55 and note the differences in sprx. Then just add the correct xml keys. For example for ps store add the #seg_commerce_new key to category_psn.xml.
.- Maybe a little bit more of charge (data) for PHAT with heat problems.
.- NO PSN hence you have to connect to devnet, you need at least one created account (From last year) the passphrase issue. So NO PSN in Dex.
But Now with 4.30 CFW out there you can do way more than a DEX PS3 can, and a Dex so far can't go higher than 4.21 -DEX
Check here too see all the guides on converting - http://www.ps3news.com/forums/ps3-guides-tutorials/