Most people will just tell you to use the search button as all this info is all ready readily available for you to research. We try not to spoonfeed, but I'm bored.
Great choice for a beginner weapon? Dunno, not bad, but wouldn't say great. Depends on a lot of things. Will you be playing outdoor only or mainly? Short of changing the spring or getting a velocity reducer this is a primarily outdoor gun. It's also one of the most expensive options, which leaves less money for other important stuff. Mags, batteries, Chargers, eye protection, and not to mention softgear like vests, BDU's, gloves, & boots. Other overlooked items include a gun case, a bb loader, silicone lube, oh and most guys like to run some sort of optics, so tac on at least another $35 for a half decent red dot. It all adds up, and when you start off with a $600+ gun you'd better have deep enough pockets to be able to actually game it.
A great choice for a beginner weapon would be an AK or Armalite variant. Tons of parts, tons of looks, tons of info on repair, maintenance and upgrades. You can start with something cheap and upgrade to get exactly what you want.
Classic Army Review
Oh and the mags with the windy things on the bottem, they are called Hi-caps for Hi Capacity(Typically around 300bbs) and come with a new gun. There are also Real Caps, low caps and mid caps but I'll let you figure out the math on those, it's not hard. Most people are into low or mids as they can be loaded with as little as a real cap, but have the capacity for more in games without ammo restrictions.