Why would you want to know what I do best and worst against? That's pretty shifty.
I've been playing a bit. Dash block works pretty well on Meta Knight! Walk block is as good as always. If the opening's obvious, you can even shield-grab from skid (for example if MK whiffs a fair as you dash into him).
Another thing that works great on Meta Knight is air-jump nair as an anti air. Air-jumps are so much better than full hops because not only do they rise quicker, but they have 1 frame start-up instead of 5. And the reason nair is so good is because of its 4-frame start-up. You still have the option to fair/uair/bair, as long as you're confident in them. Air-jump uair is an easy hit to punish MK's whiffed air-jump dair. The spacing for fair is a bit tricky, but it's good if you get the right height and tipper the kicks so opposing DI won't be dangerous. So, though nair is the easier choice, remember Fox has other powerful aerials.
Another interesting bit about shield-work against MK is his ftilt. I was playing MK against a friend of mine, and I landed ftilt1 on his shield as he dash blocked into me. He immediately usmashed! I was surprised. As he said "don't touch my shield, *****!", I thought "holy crap, the mix-up". It's common in MK play to only use ftilt1, and only continue it if it hits, to be safe. But my opponent's ability to retaliate with usmash makes it...not as safe as it should be! Throughout the ftilt, there's a chance of usmash or shield-grab from Fox. That's pretty good.
MK's dtilt still has 10 cool-down frames. With good reaction, you can shield-grab it, but you need quite a godly moment to power-block and usmash it (you'd have to predict the dtilt and be ready to usmash as soon as you blocked it).
With good shield-work and anti-air game, all that's left are details and Fox stuff, like recovery. MK quite frequently shows to be a marvelous character with his ability to take advantage of momentum anyway though. At least he's not as good as Marth at the combo stuff.
Further application for shield-grab from skid is to continue combos: regularly, only dash attack would have time to reach, but the couple frames less that a shield-grab from skid takes can be enough for it to link just in time.
Buffering may have more importance than I give it. Executing dashes and whatever ASAP allows your links to be as fluid as possible. So several of the chances to apply things like the shield-grab from skid to continue combos that I mentioned, may come after having buffered a dash. Not buffering means you're consistently missing out on around 1~3 frames. A friend of mine mentioned how noticeable my buffering ability is, so I thought that I may underrate it simply because I'm already doing it, and don't know the difference it would make if I didn't.