That's a question you may regret !
Standard gravity, 50 shot gravity, proto primo shelf gravity
Electric agitated - jt evolution, Apache 2k, Apache lcd
My fastest & more reliable feeders being 2 qloaders - but forget those as a niche product needing a lot of trial & error
But for the case in hand of force feeds - cyclone on my x7, ripclip, 2 x halo too's (sound activated and perfect for clear paint) and recently picked up a rotor as the only bidder for a nice price on eBay, and I haven't had much use to make a judgement but I have shot with a spire
There are hoppers in the above that I've left batteries in situ for years, but if i want to be sure of it then I'm inclined to take the batteries out
With a battery checker i can decide what equipment is going to get a fresh one and what will do with the ones that have been put aside
Halo too is perfectly adequate, and in the halo range there is a theory max 35bps with the v35
Maintenance is a good question for consideration. Halos need a screwdriver to strip down, but I've never needed to take one apart for maintenance. Getting an break in a hopper would be frustrating but I've managed to deal with any without major surgery
However if you're going to be looking to tournaments then there are inconveniences you can do without
You may never need to maintain more than changing a battery but the peace of mind of popping a button for a strip down can keep you confident
(But on the contrary - you never see a halos top half flying off in a tournament environment but the premium quick strip hoppers have more than one photo online of players' hoppers splitting in two during a dive - operator error is a strong factor of course)