We recently set out on week-long trek from Lescun to Gavarnie, using this book as our guide through the region. Having hiked and backpacked extensively throughout the Sierra Nevada range in California, we felt two 30-year olds in good shape should be able to make it from refuge to refuge without too much trouble. We were wrong.
Even though we mapped out the entire hike using Google Earth, which gives a mileage estimate, we weren't exactly sure how long each day's section would be since this book DOES NOT LIST DISTANCES. I find this to be a fairly major shortcoming, for such a detailed and hiking-specific publication to not have that information provided. The author must have used a GPS since he gives coordinates here and there, and it wouldn't be any added effort to have tracked the entire journey.
As a point of reference, we did not sleep in the refuges, and therefore brought our camping supplies (a 3-lb tent, and a light mat) and some food / cooking supplies. All in all, our bags probably weighed about 30-35 lbs each, but I don't feel the added weight really made a difference, since the main problem we had in completing the hike was distance.
The first day, from Lescun to Arlet, is described as a "Grade 2" difficulty hike, and is supposed to take 6hrs and 45mn. Once again, no distances were listed, but the description of "A very pleasant walk that will cause no problems on a beautiful day." had us quite reassured we wouldn't have any problems. And what a beautiful hike it was! But 8.5 hrs later, and with 12 miles (19.3km) of mostly uphill behind us, we were pretty beat. Usually when backpacking we shoot for days in the 8-10 mile range, taking us 6-7 hrs. Maybe we're wimps compared to Ton Joosten, but we had no real way of planning our trek besides using this guide.
On our second day, we set out with sore feet, but still smiling, from Artlet to Candanchu. We never made it to our destination. After climbing to the Estaens lake on a narrow mountain ledge, complete with ladders and tunnels, we had to stop to rest. We had just decended from 6,700 feet, down to 4,300, and back up to 5,700, some of the sections through the woods being extremely steep, but luckily in the shade. We decided to camp a few miles further down from the lake, 10 miles from where we started. We decided against continuing to Candanchu because we realized that staying on the guide's schedule wouldn't be much fun for people like us that like to stop and smell the roses. We were further convinced when we were awoken at 3am by strobe-light frequency lightning, warning us of the thunderstorm about to hit. Luckily we were able to foresee what was coming and packed up our tent before the hail and torrential rains really hit us, and we walked down into the safety of the trees in the valley to the parking d'Espelunguere. After drying our clothes out in the morning, we made a loop back toward Urdos on the third day, cutting our hiking trip short by 3-4 days.
All in all, I'd say this book is a great reference if you plan to hike the Haute Route. The descriptions are detailed, which is quite necessary in some sections where animal paths and hiking trails overlap and appear to go in all directions. But knowing how much you're hiking each day is just as important, and I'd even say it's dangerous to embark on a trip like this without such information. As the author states, a topo map is also a necessity since the maps in the book are just general overviews.
If we were to do this trek again, we would divide each day's section in half, doing more camping away from refuges, and perhaps mix in more GR10 and 11 routes to see some of the towns along the way.