i have used a gravity fed hopper but it doesn't compare with the halo.
kingman spyder Mr2, halo B/w rip20 oz Co2 tank, and remote
It is very fast capable of 20+ bps
Rip drive good for the chronograph
It can be hard to turn on with gloved hands
I have had this for a month, i have had my mr2 for about 2 months, as you may know the mr2 is fully automatic it is capable of the advertised 25+ bps in fully automatic but it is still too fast for the anti chop bolt, and if you have a gravity fed, it will waste alot of air, and even in the manual it says you should have a hopper capable of at least 13+ bps
I really like this product it can be bought for up $150- and for the money it cannot be beat