Only major difference is the stagefright fix but there my be a few other little tweaks thrown in so it would be a good idea to update imo. Only downside is rooting it. If you want ZVI and root, there a several stock based roms that are prerooted but you need a custom bootloader to use them.
How I did it:
TOT to ZVE > OTA update to ZVG > avicoh one-click-root > bender007 ls980 twrp autorec > any stock based rom. I personally use ultrapop 2.1 which is zvi based and it's awesome.
The ls980 lollipop autorec is hard to find so let me know if you need a copy.