I purchased one of these so I had something small but functional to use for whilst out and about so far I've been pleasantly surprised by the device.
It is easy to set up, I've had no issues setting up the wi fi, it took 5 minutes in all and it also has a good range, I'm able to use the tablet all round the house and into the back and front garden, I haven't as yet taken the device out and tried to connect to the various hotspots around, but I don't see and problems doing this.
The storage of the device is a little low (2gb) of internal storage, but micro sd cards are cheap, I got a 16gb micro sd card from amazon to expand the memory a little (16gb is plenty big enough for what I use it for, but you may want to get a 32gb one for extra storage)
Installing apps is easy enough, either from the pre-installed app market, or using downloaded files. I use dropbox to share files between our desktop pc's and thought I'd see if I could do the same with the tablet, there is a dropbox app for android that works very well, I used the usb adapter and download the app onto a usb drive to get it onto the tablet, which worked perfectly, I can now sync all my files between the tablet and my desktop.
There are a variety of apps for android, I have had trouble getting some of them onto the tablet using the web browser and through the app market, but in most cases I have found the apps for download and using dropbox to get them onto the tablet, apps like k9 which is a much better email application than the pre-installed one, I also installed opera mini on it for web browsing, which is again much better than the pre-installed browser. I have also installed the kindle app which is great, I have already read several books using it, at as the tablet is only under £100 it works out cheaper and more functional than a kindle ;-)
I've tried connecting thing like my mp3 player to the tablet and other usb devices (mice,keyboards) and all have been detected by the device and work well, although a mouse and keyboard aren't needed as the touch screen is surprisingly good, even for a cheap tablet, I have no trouble typing out an e-mail or writing notes in any one of the myriad of note taking apps, even with my sausage fingers, I did have to calibrate the touch screen to suit my fingers, but this is easily done.
The user manual is a lacking, but does cover some of the more basic functions of the tablet, although if you sit down with it and go through the various menus you can easily figure out how to do things.
The battery life isn't that great, but it does give you around 2.5 hours depending on what your doing, although having the wi fi on if you don't need it seems to drain the battery quite fast, but you still get about 2 hours, I would recommend downloading one of the task killer apps though, these apps are good for conserving battery life because even if you stop using an application it doesn't seem to close like it would on a pc, it runs in the background until you use it again, but 2.5 hours is plenty long enough for me, I have kids and sitting around for 2 hours isn't always an option ;-) I have been looking into getting a small solar powered charger for the tablet so I can charge it on the move so to speak.
I did initially have some reservations about the quality of the device because of the low price, but it's a bargain and well worth buying if you want a small and easy to use device, all in all for 90 quid it's a bargain.