I've had my Q1U (A110 800 MHz) from it's original release and have to agree with mickchip that it's (still) an excellent piece of kit. If I could find a Q1UP I'd buy it, buy I certainly wouldn't consider going for the original Q1.
I can't remember reading whether it's already been pointed out, but there were numerous versions of the Q1U. Some just had different connectivity options, but more importantly, it was sold with two different processors - the A110 which ran at 800 MHz and the A100 which only ran at 600 MHz. The difference is noticeable, don't bother with the A100. If you're daring, you can also easily overclock the A110, for a long time I ran mine at 900+ MHz
Although I haven't put an SSD in mine, nor Windows 8.1, it still runs Windows XP, XP MCE and 7 really well, but it's almost essential to do the 2GB RAM upgrade. Mine originally came with Vista and it runs that ok too unless you get trigger happy with installing stuff. Over the years I've also had it running Ubutnu and Mint too.
The other thing I'd highly recommend doing is replacing the Atheros Wifi card that it came with (assuming if/when you get one that that hasn't already been done). I had no end of problems with it and saw a massive performance increase after swapping it to an Intel 4965AGN (about £5 on ebay these days). The Atheros card problems are well documented and caused long periods of holding the CPU at 100%... which sporadically caused it to be unusable as well as eating the battery. If you do this then you can also grab come extra antennas and make use of the wireless n functionality. I actually went one step further and fitted an SMA connector for an external antenna into the unused TV aerial hole (yeh, some were sold with TV tuners too) since it was only covered with a rubber stopper. I've attached some rather blurry images of this... but you get the idea.
Anyway, since this isn't really on-topic I'll leave it there...