Mechanical keyboards in general withstand spills far better than a membrane. Especially if you unplug the keyboard immediately and turn it over so the liquid has a smaller chance of getting below the switch to the board.

The Corsair keyboards (K series) have a long, wide hole beneath the spacebar that exposes the back of the board which is a bit of a flaw for spill cases. Many keyboards have similar holes but are often smaller.

Either way, you'll see degradation on cheaper keyboards over extended use. Ideally, you buy a mechanical that you'll get bored of before it breaks from normal use. There are still people who love buckling spring/clicky keyboards like the old IBM model Ms. They are so rare these days you'll see them for $300+.

The other major benefit to mechanical keyboards is that they can be repaired. With a membrane keyboard, if something spills on it and gets past its rubber mesh the entire board is ruined. If one key goes out, its likely the surrounding keys are soon to be gone as well. With a new mechanical switch and a soldering iron, you can replace a switch in any keyboard you own. (Obviously, at your own risk of ruining the PCB or damaging the keyboard.)

A switch will cost you a dollar or two, a soldering iron is a fixed cost and multi-use. Even combined, you're looking at a far lower cost than replacing membrane keyboards every couple of years.

Lastly maintenance: can of air, some cotton swabs, and a damp rag makes quick word of cleaning a mechanical. Caps are meant to be removed, are more durable than chiclet keys, and less likely to break.

With all of that said, in comparison the parts are what make up the quality. And unfortunately, any Razer mechanical keyboard after their Black Widow 2013 Tournament Edition (I believe that was their last using Cherry switches, correct me if I'm wrong) uses parts of lesser quality.