The Windows 8 Slate is superior to the iPad because the iPad is intended for very casual gaming and internet use while the Slate Tablet is essentially a laptop without the keyboard. You can do a lot more functional computer activities with the Slate as well as gaming and other "fun" activities. the slate is a more comprehensive machine.
No, the Windows 8 tablet has years to go before it catches up to even the CURRENT iPad. The iPad is the standard for the tablet. If you don't have an iPad, you're missing out. That's as simple as it is. When it comes to tablets, Apple has changed the game as it did with the phone.
When comparing the costs of the two tablets, I have to go with the iPad. Apple still has by my top spot even though they've lacked in innovation over the last year. I'm not a fan of Windows 8, so that really seals the deal for me. Price point to price point the iPad still rules.
The iPad is the superior tablet. This is because it fits a specific sector of the buying public who likes the uniformity about Apple's products. Apple's products work in unison with each other. The Windows 8 Slate also just has mixed reviews at best. It tries to incorporate too many features at once -- features that not all tablet buyers are interested in.