Had an Alt20 for a couple of weeks and pretty impressed with it so far.
Copes as well as my Cannondale Rush on local DH trails, is happy with long day rides (more traditional xc style rides), and is generally a good sorted bike.
The adjustable fork has worked well so far - into 130mm travel for the dh trails mentioned above, 100mm for 'normal' trails.
Will be riding it for the Torchbearer 12 at 24/12 in preference to my Rush.
Wheels are heavy, stem, bars, seatpost are all cheap looking, saddle not vey nice. Grips are too thin for me. Conti Mtn King tyres are better than I thought they'd be. BUT the frame and forks are essentially what you're paying for.