This is what I was thinking, investing too much time and energy in AIXI simply because it seems to be the most 'obvious' option currently available could blind you to other avenues of approach.
I think you should know the central construction, it's simple enough (half of Hutter's "gentle introduction" would suffice). But at least read some good textbooks (such as AIMA) that give you overview of the field before charting exploration of primary literature (not sure if you mentioned before what's your current background).
I searched the posts but didn't find a great deal of relevant information. Has anyone taken a serious crack at it, preferably someone who would like to share their thoughts? Is the material worthwhile? Are there any dubious portions or any sections one might want to avoid reading (either due to bad ideas or for time saving reasons)? I'm considering investing a chunk of time into investigating Legg's work so any feedback would be much appreciated, and it seems likely that there might be others who would like some perspective on it as well.