Personally, I'm going with xk3y, and for a few reasons...
1 - Support. The xk3y has deticated forums for support and general discussion; something the Wasabi team does not offer; they only have an email address. One of the main devs for the xk3y posts on the forums regularly, and they are always looking for customer input in regards to future firmware updates and the like. Again, Wasabi doesn't have anything like that.
2 - Yes, having to get the drive key manually extracted can be a bit pricey if you're unable to find someone to do it for you (I got lucky and was able to find someone to do it for a trade). However, while it is nice that the Wasabi can auto-extract it, it also requires the bin file (and the other accompanying files) to be stored on whichever storage device you're using. The xk3y stores its files on board via microSD card, which means you can easily switch out multiple storage devices (or use them all at once) without having to worry about making sure that those crucial files are on each device. ...and if they aren't on there, there's no risk of accidently deleting them.
3 - Speaking of storage devices, the Wasabi requires an eSATA interface. While I haven't done much looking myself, with the few larger storage devices that I have seen, they all seemed to be USB 2 or 3 rather than eSATA. Wasabi claims to have an adapter in development the can go from USB to eSATA, but I've heard nothing more aside from that. The xk3y uses the good ol' USB interface, so you can use ANY storage device, be it an external HDD, flash drive, etc. Also, I believe the USB adapter for the xk3y may be USB 3 compliant, but I'm not entirely sure.
4 -The xk3y supports numerous files systems, such as FAT, FAT32, NTFS, and EXT3 and 4 which, from what I've heard from numerous users, offers the best stability and performance. Though it does require a little bit of work to use that particular filesystem on a Windows machine.
4 - The Wasabi requires physical modification to the console's metal frame to allow the cables to connect to the Wasabi housing. Also, because this housing directly connects to the console's case, it makes it that much more difficult to take apart again in the future should you need to do so.
Again, these just some of the reasons that I personally am going with an xk3y. You of course have your opinions and are free to choose whichever device you like the most.