I know this is my first post, and i am very new to this hobby (i'm just starting my first project now), but what I found about Aspen wood, is that it is very similar to basswood in almost everyway. The only difference is that Basswood soaks up stain like a sponge, meanwhile Aspen reacts like normal woods. In addition to this, Aspen is in the Poplar family. So, I figure that you can expect a tonal range from Basswood to Poplar. Most info on the net that I found stated that it would be a great lead guitar body wood (comparing it to poplar and basswood), and will lend you a warm tone. As for a neck wood. I recommend using a harder wood to increase neck strength. I am going to use Aspen for my body on my first project and maple for the neck.
Joe