They are adjustable, there are set screws on the top of the magazine to get rid of "wobble".
The can be disassembled and cleaned.
They are almost indestructable.
I have the composite ones, at $45 buck a pop they are expensive...but you get what you pay for. I have had 2 of these for over a year now and cleaned them once. They work as good as the day I bought them.
Here is a link to a review I did way back in the day...
...and yes they are currently backordered :)
...that is all.