Had one for about two months
For my wife, actually. My goal was to allow her to browse the web, mess around on Facebook, etc on something besides my laptop. So far, so good. My review in a nutshell is that this device won't knock your socks off, but it is a good deal for the price. I did install the Google Apps support (which was simple -- just the same as installing any other APK), and that improves the device's usefulness significantly.
FWIW, I also had the archos 70 for myself until I cracked the screen (my fault).
The media player functionality is quite good. We no longer drag out the portable DVD player for long car trips because the kids can watch videos on the archos.
One quibble might be that none of the apps are designed to take advantage of the larger screen, but in practice this is not that big of a deal. It would be nice to have, but isn't a fatal flaw. Dolphin browser actually works quite nicely on the device -- you can take advantage of the tabs and sidebars. In both devices, you can comfortably browse web sites in landscape mode and view the "real" web site rather than the mobile version.
Performance is generally pretty good. I suspect that the archos *could* run Honeycomb, but will archos provide the update? (I'm guessing no)
Between the 101 and the 70, I actually liked the 70 a little better. It was more comfortable to operate for longer period, at least for me, and I didn't mind giving up the extra pixels.