[Zack The Ripper]

PDI W-Hold rubbers are good. They will cause a slight drop in your velocity, anywhere between 5-15fps depending on your overall air seal in your barrel grouping as a whole - some brands of rubbers are thinner than others, some hop up units have tighter tolerances than others. I find the W Hold rubber stiffens in cooler temperatures. This means that the first few shots will be inconsistent until the rubber "warms up" from the friction of feeding, then it's glamour shots from there. This usually only occurs in temps under 10 degrees Celsius. Overall, not a bad starting point.

RHop, IR Hop, and ER Hop are all fancier methods to create a large contact patch for the BB to grip to. These take a skilled hand to do correctly. Very accurate and most importantly consistent compared to most methods.

Flat Hop and Bridge Hop are solid. They get comparable results to the R Hop methods above, though not quite as fine tuned. Still, very accurate and consistent.

Prometheus purple rubber gave me fantastic range and accuracy using a Prometheus tight bore barrel for the better part of last year. Was getting out beyond 250 feet at 395fps on a 300mm inner barrel using 0.30g BBs. About 220feet of EFFECTIVE range. I am now using a bridge hop setup for me by pestobanana. Have only been doing indoor play with lightweight rounds, so haven't been able to max out effectiveness yet. More testing will come when the weather warms up. Hoping it will have pushed the effective range out to that 250 foot nark, but time will tell.

Start with the least expensive methods, play around with it for awhile, and then move on up the ladder to see personally what gives you better results. More fancy, more expensive methods aren't always the best solution for some guns, you'd be surprised.