Yeah I'm a subscriber, have been since they went online. I'm not a GURPS player, but I have 2 dozen or so of their sourcebooks and generally they are great for background. The same goes for the online subscription, and to be honest I really love the idea of getting new gaming content every Friday instead of once a month. Generally I'd say it is pretty good, sometimes the content is a bit weak, like this weeks April Fools stuff (not a big fan of goofy stuff in my gaming content) tho' it is much better than getting an entire Dragon magazine of the stuff and having a whole month ruined.
Anyhow, I'd recommend it as the background information is great and they are becoming less GURPS specific and moving more into generic info (I've even read a couple really good D20 articles).