Ok guys we tested the possibilities on firmware 1.52 for a few days now. What I can confirm is the following:
Tech4's exploit still works
Wololo's HBL still works
everything I research atm didn't change from 1.50 to 1.52
If that is fine for you, there's no reason not to update.
Anyways, I have to mention that this can change without a firmware upgrade!
If you are online with your PS VITA, it can download and install silent updates for any application which runs in usermode and has nothing to do with system critical modules.
The good is, those updates are removed once the system is restored to the current firmware, so it would not be a major problem to remove a fix.