I started playing around with the beta a few weeks ago, and today I became a paying customer.
The bad news though, is that every time I open the thing, I get sucked in. For example, about fifteen minutes elapsed between the words "paying customer" and "The bad news", during which I double checked some information on Gosnold, MA (population 86), visited the site of Ted Kennedy's famous car crash, and learned about a proposed offshore wind power project off the shore of Nantucket.
I'm one of those people that is always hungry for information, regardless of its worth, so having a bunch of terabytes of data presented in an easily browsable and contextually relevant manner... let's just say that I'm getting better at geography.
The downside is that because of the sheer volume of data, most people aren't going to have the full experience of seamless navigation. There's a huge difference between my computer at work and the one at home. At work I've got a generic office computer hooked to a T1, and things are relatively slow to load compared to my gaming rig on a cable modem that's juiced up to the point that it rivals the office connection I had when I worked for an ISP. Overall though, I'd say that even when it's slow, the software is worth playing around with.