Yes, I own this router.
As a router, it's fine. Very "normal" Linksys offering when it comes down to it. I always have full signal strength, but then again I can't get very far from it (never further than 75 feet in a straight line between me and the router.) I also don't have any real challenges like extra thick walls or walls made out of materials that are really going to challenge a radio signal.
The guest network feature is also very nice. If you had more than 10 guests that wanted to hook up to your network at one time, I guess it could be a problem, but I've never come close to that.
As a wired router, it's even more unremarkable.
I will say that I've had to reset it twice since I got it in July. Though those instances were all related to use of the built-in media server and the built-in USB port.
Both are poorly implemented and are no longer in use here.
I actually "lost" data on a hard-drive plugged into USB port. I had copies elsewhere, hence the quotes on lost, but if I hadn't had those copies, I'd have had to try and recover the data. The USB drive in question had no issues prior to use with the router and has had none since. As a matter of full disclosure, I should say that the issues occurred when I tried to write to the drive; if you can write from a computer and then transfer the disk to the router, that seems to be fine, but archaic.
The Twonky server is an emasculated version that locks you away from common configuration features. If all your video, music, and photos are encoded the way Linksys seems to think that they should be, that's not a problem. If you have video, music, or photos that are encoded in different ways they won't play and there's no way to tweak Twonky to get them to play.
So reality says that I don't trust the USB port and I just use the desktop version of Twonky I had before.
The E4200 is a good dual band router, but that's it. I only paid $10 more for it than the E3000 (or was it E3200) that was right next to it on the shelf so I don't feel particularly aggrieved, but I wouldn't recommend the device to for those additional features.
Edited by Florida_Dan - 10/15/11 at 9:49pm