I had a go on my mates new 18" 2011 Orange 5 last week.
Normally i ride a Cotic Soul or Turner Flux which both have a 24" TT and being 6' with a fairly long reach the bike seemed a little on the short side.
Overall the bike felt great and didn't seem to notice the slack HA even on twisty single track, tapered head-tube makes the front end feel very solid and it looks atheistically pleasing unlike some other tapered HT bikes.
If i was looking for a bike mainly for this country and occaisonally for steeper trails abroad i'd get the 5 (or 5AM) if you want the bike mainly for abroad then i'd go for the Alpine.
Looking at the Alpine myself but won't be bothering until 30.9 seat-tube and tapered head is standard,