Adjustable gas is much better than a fixed gas block. If you take care of your equipment & make it part of your maintenance, you won't have an issue. I've got a jp adjustable block on my rifle that I've not adjusted for 3 yrs that has never failed.
The last adjustable gas block I used was a Seekins with the brass set screw. I didn't have any troubles with it coming out of adjustment.
I just had so much troubles with the KIES gas block in the past that I couldn't put full faith into adjustables anymore so I switched to a regular gas block.