About a year ago, my derailleur hanger suddenly snapped, causing the rear derailleur to take out my Easton rear wheel in a low speed crash. Since the Easton wheel was relatively old, I couldn't find a replacement, and I had to look for a replacement wheelset. I've always liked the look of the Ksyrium ES's, so after a quick scan of Craigslist and eBay, I bought a set for $400 from some guy in Santa Monica.
I've got nothing but praises for this wheelset. I'm 210 lbs, ride on sometimes crappy roads, and this is a six year old wheelset, but I've seen none of the stress fractures or other damage reported by other reviewers. I recently had the hubs serviced by my LBS, and they said the wheels still have plenty of life on them. The mechanic actually offered to buy them from me, if I was willing to sell, but I'm going to hang on to these for as long as they work. I've never had to have then trued, so they're pretty tough, too.
The sidewall stickers are a little busy for my taste, so I took them off with some nail polish remover and elbow grease. The red hub paint is little faded, and the spokes show some scratches, but overall these wheels still look great.
Overall, a great replacement wheelset for an affordable price.
Weaknesses: None if you know what they are before you buy. They are not TT wheels or climbing wheels for sprites.
The rear wheel developed some cracks around the spoke nipples because I hit a pot hole so hard it rattled my brain and cause my bars to drop! Mavic sent me a new wheel at cost $175. No bearing issues. No complaints.
Strengths: Good looks - red hub, red spoke as accent.
Weaknesses: Plagued with long-term reliability issues. Best kept for race day, not daily training.
This is kinda moot since the ES series rim was discontinued in 2007, except that the newer SL Premiums appear to have many of the same design characteristics. I purchased these as upgrades to Ksyrium Elites that came on my Scott Addict. They look great, but suffered from two reliability issues - paint and fatigue life. First, the red hub started peeling from the hub. I was told this was caused by solvents, but I use the same cycling-specific cleaners/lubes on the rest of my bike and this is the only part that had issues. Strikes me as more of a defect. The second, and bigger issue was that the rim failed after probably less than two years of use. A spoke broke unexpectedly, and was unrepairable due to a long crack at the spoke eyelet. I realize there is a tradeoff between light weight and durability, and that aluminum parts don't last forever, but I've not had these issues with other rims and wheelsets in the past.
Durability, Stiffness, Weight and THEY LOOK GOOD!!
I have read a significant number of reviews about these wheels, many that knocked them for reliability. However, at over 200lbs, knocking down 80-100 miles/week, I have nothing but good things to say about these wheels. I have two sets of these wheels on two bikes. I got my first set with a new bike and then got the second on eBay because I liked them so much. I usually ride local roads, so they have seen their share of pot holes and other road obstacles. Over the past years, I have replaced one spoke (on the front wheel, not the rear!) and had one wheel trued. Maybe I should have expected more, but every time I exit a pot hole, continuing to roll straight and true, I gain confidence in the Mavic brand.
Weaknesses: spokes are proprietary and expensive, but you will likely never have to replace them. Not cheap
I have read a lot of reviews complaining about durability reliability of these wheels. I am not sure what the issue is but I do know that there is a weight limit on these wheels. They are very light and not intended for heavier riders. I have 20,000+ miles on mine and after three years I have not so much as adjusted the hub preload or adjusted a single spoke. The bearings are still going strong and spin as smooth today as they did on my first ride. I have 7 bikes and they all have Mavic Ksyriums. I have one ES and the rest of the them are the SLs. Of the seven sets of wheels, I have never had a spoke break and have only one rear wheel go out of true (I think it was due to poor baggage handling when I traveled with my bike.) I have only had to replace the bearing in one wheels set. Mavic Ksyriums are truly high quality wheels and when properly cared for will give years of trouble free service. I have seven sets of these wheels with over 100K miles total so I do speak from experience.