I have had my 2015 R5 for nearly 2 years (and 21,000km) now, and I still love it. It's by far the most comfortable road bike I've ever ridden.
It's definitely suited to going up hill, which suits my preferred riding locations, but Cervélo have put a lot of effort into making sure it is still very fast into the wind. I've raced single day road races, multi-day tours, and criteriums on the R5 and have never had an excuse to blame the bike for a bad performance.
The standard HED Ardennes+ are comparable in weight to the Shimano C24s I had before I bought the bike, although the 25mm width helps them absorb the bumps and makes descending a far more pleasant experience.
I opted for the mechanical DA version and I haven't had any issues. I had to replace the rear derailleur after 20,000km, which felt reasonable to me. I did have some trouble with a small crack in the frame, which appeared at about 20,000km, although Cervélo (via NCC) were quick to rectify this by supplying me with a replacement frame.
Not to be outdone his training mate, fellow Cervelo R5 and NorthCC rider Manny has chimed in the a review of his own
Cervelo pride themselves on continued development and improvement which is illustrated in their flagship model the RCA. Even though the R5 does not include all the amazing features of the RCA as a complete bike, it does have all the benefits of the RCA frame without the added cost burden that comes with such luxury. It is a lightweight bike aimed for the climbing conscious cyclist and while the bike does perform extremely well in the hills, it is when the road turns downward that the true nature of the R5 reveals itself as a wind defying speed demon.
I currently run Curve’s 38mm x 25mm wheel set which are amazingly fast the race season as well as generously comfortable for those longer days in the saddle. The HED Ardennes + which come standard with the bike are no slouch either. My R5 is equipped with Shimano di2; precise shifting every time!
I have had the bike for a little under 2 years and needless to say, they have been my most enjoyable two years on a bike. I have ridden over 20,000 km, have been fitted to the bike by RiderFit (aka Stewart Morton) and with regular services from NCC, I’m looking forward to a long happy future with my Cervelo R5.