I rode this in summer 2008 and still remember it vividly!
1st half, nothing unusual as mountain roads go, the Alto de Tenebredo (also on my + Vuelta 2011 route) was a lot steeper (sections of 15% +).
But then the second half... oh boy! It reminded me of the "The Devil's staircase" in wales
http://www.sportivecentral.com/index.php?p=climbs&rid=130&page=3
only much, MUCH longer!
Unlike the Alps, on the climb there was just about no one around - I stopped and asked / gestured to a couple of blokes (chasing a donkey if I remember correctly - no jokes please!) if it got any easier. They shook their heads grimly and gestured 45 degrees with their hands!
On the 23.5% bit I was struggling in 22 x 32 on a mountain bike!! Oh yes, and in preparation for the Vuelta they were resurfacing the road so there were occasional lorries, diggers (and even a steam roller) going by and best of all, the whole second half was covered in loose gravel. Great!
Check out Pedro Delgado having a tough time in 34 x 28 on a road bike - but he still manages to chat to Chucho Rubiera all the way up. (Spaniards - what are they like?!)
http://www.rtve.es/alacarta/videos/vuelta-ciclista-a-espana/pericopuertos-langliru/1188711/
Interestingly, on the way down I saw a v high end cyclist (complete with TWO motor cycle outriders with hazard lights flashing) going up - no time to stop and check out exactly who it was but likely a pro doing a recce of the climb pre -vuelta.
I've ridden a lot of mountains before and since notably the Iseran (from the south) and Cormet de Roselend (from North) - lovely scenery, a much 'nicer' experience but NOTHING compared to l'Angliru!!
Forget Alpe d'Huez, get a plane to Oviedo / ferry to Santander or Bilbao and check it out for yourself - you won't forget it in a hurry!!
(then pop down to Granada Province and ride from "Guapa" at sea level, straight up the side of a cliff to "Sierra de lujar" almost 1900 m in less than 30 km with 200km views all the way to Gibraltar and Africa - should blow out the tubes!)
See Climb No 6 on
http://apmforo.mforos.com/401631/9894004-puertos-para-un-posible-final-de--de-240-apm-de-coe/?pag=3