I believe I mentioned drilled rotors that cost $$$, which you could roughly group Porsche into I believe. Cross drilled are fine, but cheap cross drilled rotors are likely to crack. The reason rotors are cross drilled is to make a gas port into the vent vanes in a vented rotor. There are also some cooling effects by moving air through the holes from the vanes. If you don't have vented rotors, it's of absolutely no use to cross drill them. Even worse, the only thing that it does (in non-vented rotors) is make nice stress risers to concentrate loads during thermal expansion and braking, propogating cracks at the holes. This is why slotting started, there are no issues like that.
The reason good quality rotors (Brembo, etc) can do cross drilling without problems is because they can manufacture the rotors well enough to minimize the effects of the stress concentrations. Basically, if the rotors are overbuilt and plenty strong, a little weakening isn't going to be an issue. Not so with cheap cross drilled rotors. The manufacturing process is very critical in the drilled holes and how they are stress relieved, chamfered, etc.

It's a myth about slotted rotors eating pads, they're a little rougher than blank rotors on pads, but they're great other than that. I'm sure cheap slotted rotors could have different problems than decent slotted rotors though, so it's probably possible that crap slotted rotors may eat pads faster due to shitty manufacturing. There are some pretty shitty rotors out on the market, both cross drilled and slotted.
Slotted rotors have most of the benefits and none of the drawbacks of drilled rotors, and usually last longer for street use.
Once you start getting into big money, good quality brakes, the differences blur and are really down to the application.

So here's my recommendation:
For the street, for normal use, slotted work great. For more extreme use, or race use, go with cross drilled, but you're looking at a lot more $$$ for anything worth having that you can rely on.
THere are very good advantages to cross drilled rotors, but you're not going to get those advantages in anything that's cheap or a stock replacement.

If you really want cross drilled, check out some of the combination slotted/cross drilled rotors, they're not cheap either though usually.