That's right. You don't HAVE to pay more money to get a nice quality metal slide... Instead, you just get a crappy metal slide right out of the box when you buy a WE!
j/k... sorta. I love bashing WE, but the truth is, you get a lot of bang for your buck if you're looking at an out-of-the-box pistol experience.
Accuracy and performance has NEVER been a strong point of WE, and despite being out for so many years, they've done nothing to improve that. They had a huge gap to fill as far as durability and they're still patching that up now. The wobble between the inner barrel and outer barrel - and again between the outer barrel and the slide - and again between the slide and the receiver have always been horrendous, IMHO.
If you're looking for a platform for upgrading, just skip over the WE and get a Marui. You DO get what you pay for, when you're buying a Marui versus a clone.
But if you're just looking for a gun to do some <20' bedroom plinking for sh!tz and gigglez, then a WE can get you there, all metal for a low price.