I changed mine with an Ohlins because when braking, the rear part of the bike was going up too much for me.
I don't like that behaviour.
I admit that my HP2E has never seen dirt roads more than 0,01% of the time I ride it.
Perhaps the air shock is good in dirt type of ride with 21" front wheel, I don't know.
2014 KTM EXC450 6Days
2008 HP2/MM ABS
2005 HP2E SM Prototype