What are the advantages and risks of flashing a custom ROM?
There tend to be many for either side, I can list a few bigger ones:
Pros:
-faster...much faster updates. Take for example my M8. Stock ROM is on 4.4.3. I have been running 4.4.4 for quite some time.
-reduced if not eliminated bloat.
-features that Stock doesn't offer, i.e. changing the status bar look, lockscreen wallpapers, CPU tweaking, etc.
Cons:
-Depending on who the developer is (Cyanogen, AOKP, Slim) stable releases are usually not very fast. There are versions called 'Nightlies' that have bugs, but most bugs are minor. I am on Liquidsmooth and occasionally, I get UI crashes, but they don't really bother me. It's not like a bug is 'my phone doesn't work'
-For a first timer, it can seem unnerving, as you can potentially brick your device if you flash the wrong ROM.
Going to turn it around. What are you looking for in a ROM? Say, for instance, do you want OTA updates?