The iLiad has a lot of potential. The hardware is very nice, but saying that the software lacks polish is quite charitable. The WiFi support is about what I would expect from a 2.4 Linux kernel, which is to say not quite nonexistent, but close enough. The PDF reader is just about acceptable, but lacks features like the ability to jump to bookmarks (very frustrating when reading a large textbook that you know has bookmarks for every chapter and section) and the ability to display pages one-half page at a time, which would be useful for a lot of PDFs with very small text. Installing the community version improves matters a lot, but iRex really needs to start folding these changes into the official version soon.
The only real problem I had with the hardware was an intermittent fault with the Wacom tablet, which would periodically think that I was clicking in the lower-right corner of the screen (causing me to jump to the end of the book). Everything else I disliked about the device was related to the software, and therefore fixable.
As a development platform, the iLiad is quite interesting. It has a fairly standard Linux kernel and X11 display, with slight modifications to the X protocol to allow for efficient partial updates of the screen. The included software uses GTK. If you register as a developer (it's free), your iLiad is unlocked, allowing you to run shell scripts as root. From here you can install third-party software easily.