Love the Cristalpl a pretty amazing event, its does have fire road climbs, but it also has a few nice bits of singletrack here and there, some big fire road descents, the last section after the reservoir is technical and catches a lot of people out, the gravel fire road to the finish also catches people (seen the helicopter winching rider off)
But its more about the whole atmosphere, its just epic, who gives a frig of its technical or not, its just a brilliant big event that will push you to your limit. The massive hike a bike lined with people with bells and horns and cheering is just brilliant.
I like to do it as part of a week or two week break to give myself a chance to get used to the riding and the height.
lots of brits there, but next on the list is the mega and the rtansvesubienne. Once you have done it you will ask yourself why cant we have events like it in the UK.