there have been a LOT of improvements to many P2 system in the newer firmwares, but there are also some restrictions. This is only my opinion but imo the 2 biggest are thus in latest firmware vs 1.8
1) descent rate limit. In v1.x there wasn't any. In version 3.2 you will be limited to 2 meters/sec descent rate. that means if you're holding the throttle full down the Phantom just slowly descends at 2m/s, period. This was implemented to help newer pilots avoid VRS and crashing their Phantoms which apparently was happening a LOT
2) flight area restrictions. in latest firmware there are no-fly zones of roughly 5 miles from major and many minor airports. This is in line with FAA restrictions, so honestly this shouldn't be a problem for you, but it happens here from time to time someone is like "why won't my Phantom spin up the props anymore" and they realize they're like 4 miles from an airport.
If neither of those things really bothers you, I would say yes upgrade the firmware and get all the other benefits. They've improved battery management/flight times a little, compass issues and plenty of other bugs.
Then again if you are 100% perfectly happy with how your device currently operates maybe if it ain't broke you shouldn't bother fixing it.
It's pretty easy to go locate the "release notes" for the latest firmware, read back through it and keep scrolling down to the history and you will see in the notes all the changes they made in the various firmwares. Here's that link:
http://download.dji-innovations.com/dow ... tes_en.pdf