As long as you have your 4.2b3 SHSH blobs saved and you are a dev (so you can acquire the 4.2b3 ipsw 'legally'- no UDID needed since you won't be actually be restoring to the 4.2b3 fw), yes, you can do the Monte jailbreak (redsn0w 0.9.7b6, Mac OS X only).
Most of the previous issues with the Monte jailbreak has been resolved- Bluetooth and Skype are work fine now. iBooks does not work for protected books (most books from the iBookstore are protected with some exceptions) but books you load yourself (epub and pdf via iTunes) work fine.
Current solutions is tethered 4.2.1 JB or untethered if you had 4.2beta 3 blobs.
Or if you had 4.1 shsh's you can downgrade back to that for an untethered JB.