He introduced HPA because you can convert any gas sniper rifle to use HPA. which pretty much makes its disadvantage of behaving poorly in colder climates go away.
If you already have an hpa tank and regulator, its a very cheap upgrade. Send it in to bingoairsoftworks.com. And he will convert the mag for like 25 bucks.
In the pac nw, i wouldnt own a non-hpa gas sniping rifle. Since the temperature differences between morning and afternoon alone are pretty large. Not to mention its 48 degrees and cloudy in every season except for summer. So if you dont want to fork money over on an HPA conversion. I would go with a spring powered bolty.