You probably know that Windows 8 comes in two different versions - Basic x86 Windows (this is what you use now) and Windows RT. They have similar names. They look the same. But there are serious differences between the two - ones you should know about before you plunk down your cold hard cash on a Microsoft tablet.
Surface—and other Windows tablets that follow it - will come in both Windows RT and full Windows varietals. Which is great! More choice is always better. The problem you're going to run into, though, is that the gap between RT and x86 is as wide as that between iOS and OS X - except the two Windows offerings look exactly the same at first blush.
There are a ton of benefits to using RT, like better battery life, lighter weight devices, cheaper price points. But there are limitations, too. Here are a few of the big ones.