I've got to say that after a quick look, I think it's a great start! Everything seems a little large, so it seems to be better suited to a larger screen. I had to zoom it out a bit when viewing.
I really like how all different specs on the guitars are intertwined. No matter what spec is listed, ALL the corresponding models that include that spec are listed, then from any of the listed guitars, any new spec can be selected to redefine the list. It would be cool if you could select more than one spec to be used to build the list of results (for instance if I wanted to see all rosewood bodied, GS guits, etc). The lists are sortable, but I wish it could have a selectable format (like small icons). The large images don't allow for much to be viewed on the screen at once. I also like how the shape and wood info is now integrated into the guitar section and not in the separate resource section.
Overall, I find it VERY easy to quickly view and compare the various models, specs, etc. I think it would have make sifting though all the various series and models much easier a few months ago when I purchased my guitar.