Hi,
I would have a look at the new features introduced in 4.4.1:
http://www.cisco.com/en/US/docs/app_ntwk_services/waas/waas/v441/release/notes/ws441xrn.html#wp105332
If you want to use any of these, I would consider upgrading to that one.
If not, I would stick to 4.3.1 since there are been a couple of code changes in 4.4.1 (DRE for instance) and you might want to wait for a couple of interims before moving to this version if you are not planning to use any of the new features.
If you do, the only thing I can tell you is that we haven't seen much 4.4.1 cases in TAC since it was released so it seems to be pretty stable already
PS: If you are still using legacy CIFS, just keep in mind that it has been completely removed from 4.4.1 so you'll need to migrate to CIFS AO before the upgrade.
Regards,
Nicolas