The lever lock feedneck design is the most convienant on the market. No tools required to get your hopper on and get a grip that will never let go. Leave the lever loose, insert the hopper, tighten the finger knob until there is slight resistance, close the lever, play paintball. NO TOOLS REQUIRED. Tested to fit all hoppers with no shaving or electrical tape. Made with aircraft-grade aluminum. Making them very durable and light.
The XSV Paintball Feedneck is newer, so it should be commonly available, both new and used.