They're a lot of fun to shoot! Looks like you have the 22 Round Mags. Search around the Web for Spares, and you'll find them at decent prices. Most Sold, are usually Twin Packs. Mine shoots WWB 36gr 1280fps just fine. No problems with that Ammo. Here's a Break-Down & Cleaning Video for you.
Not as easy as an AR, but simple enough. Keep it clean after every Range Visit, and it'll last. Just keep track of your Pins, Springs & Tools, and you'll be fine. I have the SDR Model, and have done a few Upgrades to it, using the GSG-5/522 Conversion Kit. I also removed the Stock, and added the Retractable Stock and Upgraded Push Pins.
Here's a pic of mine, with a Vortex StrikeFire Red/Green Dot Scope.