Hey Joe
The L12 will have a Sitka Spruce top, it's stiffer than Cedar and gives a good punchy, strong bass response and very clear trebles and will probably take about 2 years or so to fully open up as it starts to mature.
The L10 Cedar is a softer option giving lovely smooth sound, well rounded clean tones.
Why not go here and download some of our sound files.
http://www.avalonguitars.co.uk/shop/index.cfm?do=listen
These are hi-quality mp3 files and will sound good if you've got decent PC speakers but if you don't my advice would be the convert them to wave files and burn an audio CD and use your hi-fi for the full effect.