Sorry to resurrect an old thread, but I couldn't help but chime in.
Most of the players in Storm use warps, and no we don't get given them, we have to buy them like everybody else. We're not required to use them at all- a fact demonstrated by some of our players not using them.
Personally once I had used a warp fed 'Mag nothing else would do. The main advantage is the marker profile, regardless of what anyone says. When used correctly the only exposed profile you have round or over a bunker is one eye and one barrel. Nothing else. The only way to get tighter is not to look while you fire. Yes, you can keep tight with a conventional hopper layout but you cannot leave a one-eye-one-barrel profile- it's impossible unless you have your hopper hanging off at an angle. When angling the hopper inwards as you should, you are always moving your gripframe and hand outwards. You have to compensate by pressing the barrel and marker into the bunker. Works for a lot of people, but the warp gives you different options.
Potting up is also much easier- keep the marker in your shoulder, your finger on the trigger, your target in front of the barrel and pour the paint in. With practise you can do it without shifting position or flailing your other hand around.
The other big advantage I find is that as a right handed player I can wrap both sides round a bunker without significantly changing grip or stance. Useful for a back player quickly switching to a line shot, or a front player varying his snapshots to keep the opposition guessing. Also having 20+ shots waiting ready to be force fed at 24balls per second regardless of the marker's attitude is very useful. It's basically a fast ball "cache".
I have never had a ball break in my warp, even with direct hits. If it did happen I doubt it would be any more sever than a break in the breech anyway- it will fire through shortly. Mis-shapen balls have jammed mine on the odd occasion using cheap training paint, but then they would likely have caused problems when they got to the breech anyway.
Disadvantages? Weight, yes they do add weight but in the heat of a game I've never noticed. Between games I
have noticed admittedly! It's an extra electronic system which means when it goes down it's impossible to fire. You can power them off your marker battery however, and there are kits available to power a warp and hopper off your E/X-Mag battery, which is easily big enough for the task.
I think the main reason you don't see them on a lot of markers are because they are really designed around Automags, or rather the Automag has been (re)designed with the side fed bodies to suit the warp. Most top center fed markers require an unsightly top feed adapter which adds profile and means you still can't see along the top of the marker (not that it really matters- most good players shoot by well-practised instinct anyway not by sighting along the barrel)
Warps ain't for everyone but, like the Z/Y-grips, they do have a very good reason for existence, and it isn't to make someone a fortune. It's a tool and it allows a different style of play with some supplementary advantages and disadvantages.
I always like to remember a quote at a recent tourney where we did particularly well. We overheard a player on the team we had just beaten saying to the team we were about to play "If you see them looking, then shoot, 'cos they ain't just looking!"