0.) The first important thing to note is that you CAN change the bag in an Easy Valve, multiple times if you’re careful before they need to be replaced. There are multiple guides on this online, I like the prying methods best. This means you can get multiple uses of each valve, saving $, that you can clean them before reuse too so they’re like new, and that you can customize your bag sizes too just like a Solid valve.
1.) The width of the chamber and screens in the EASY valve is wider by around a 1/4″ – which is quite signifigant. This leads to greater exposed surface area and faster production of vapor. This also makes for an easier cleaning chamber.
2.) The Easy Valve kits give you multiple mouth pieces and valves. Each kit gives you more. With the Solid Valve, unless you by extra (that’s a lot of $), you only have one. What this means is that you can rapidly fill multiple bags – one for each person, or one right after eachother… great for having many people over.
3.) Having multiple bags and valves with an Easy Valve also means that you can have multiple bag sizes, ready to go immediately. Maybe a 1 footer for just yourself for quick sessions, a 2 footer for just you or you and one other, a turkey bag or two for pillow like bags that don’t crinkle for “stealth” or “quiet” times, etc. all the way up to having huge 10′ bags by using a whole roll of solid valve material at once!
4.) The chamber of the Easy valve is MUCH more simple and easy to clean. It has far less tendency to get sticky / gummed up. It’s much easier to take apart and assemble. No moving parts like the silly upper screen in the Solid Valve you have to remove and clean constantly each time you fill. Filling it is much simpler as you just twist and fill. It’s much smaller making it easier to clean too and completely disassembles. There are far less parts used too. It’s smaller and takes up less room. All in all, it’s a much better chamber design.
5.) The chamber for the easy valve clips onto the volcano very securely, so the bag and chamber don’t want to tip over or fall off like a Solid valve can/does. So you don’t need to hold it at all during filling.

Yes, the valves on the bag and mouthpiece feel less overengineered and “solid” on an Easy Valve. Yes they feel a little cheaper. Yes it’s not AS easy to change the bag… but to me the pros far out weigh the cons.