See, this is the rub that a lot of people aren't thinking about. While finally having a jailbreak will be amazing, if you don't have a way to downgrade, it could be just a temporary thing. Let me explain...
We've all installed something that didn't agree with our phones from Cydia. It happens. Normally, you'd just do a restore, select the firmware you want to be on (provided you had your shsh's for that firmware), then re-jailbreak.
But with the A5 devices, until they come up with a way to downgrade, if you have to do a restore, you can only restore to firmware that Apple is still signing. If the jailbreak is for 5.0.1 (or even 5.1) and 5.2 is out, thus 5.0.1 or 5.1 aren't being signed anymore, you won't be able to downgrade and won't be able to jailbreak (unless there's a jailbreak for 5.2, for example).
Just hope you don't run into any problems and need a restore.