These are quite easily the strongest spokes on the market, able to withstand forces that occasionally belie belief! One of the guys here has witnessed a rear mech sliced in half when coming into contact with a spinning wheel.
We use these for all applications. They first came to prominence in Downhill MTB World Cup racing. The crossover to road use has been a major breakthrough - but it has taken years for Sapim to catch up with global demand for the spectrum of lengths required.
They have round butted ends and a flattened central section. Not "bladed" as such as they are only 2.1mm wide. Due to the design, these spokes cannot properly be cut and threaded, therefore we keep around 20,000 Sapim CX-Ray spokes in stock at all times. Not for retail sale however, just for building.
They are not immune to breakages though - it is common for pedals to take a few out in race incidents, but due to their ability to stay stable under tension, even a 20h front wheel can stay relatively rideable with a broken spoke. They are made out of very high quality stainless steel, rolled flat to add extra strength. Tension does dissipate over time, slower than with conventional spokes but as we build them to very tight tolerances of relative tension, they will stay true for a long time to come. In general use, tension should be checked annually and brought back up if required.
ACI Stainless double-butted:
We keep these for cheaper and classic builds. They are excellent spokes - are 20% Chromium, fit hub holes nicely with a smooth bend & nicely rolled thread. Very few breakages over the years, they seem to bend in crashes too and we use Purple Extreme lube to combat corrosion from winter crud. We have built wheels for global-touring, downhill racing and almost all other applications with these spokes over the years - with NO premature failures of any kind. Amazing quality.
Sapim Laser spokes on the front wheel compliment ACI on the rear for a traditional looking wheelset with a little but of weight loss on the front. There are other thin spokes on the market, they are usually dreadful. Lasers are excellent.
Note that Sapim Lasers are not usually suited to use on the rear wheel where a lot of torques come into play - especially if you are heavier. Although they are the same weight as CX-Rays, they do not stand up to these dynamics well and are more suited to front use only. Ideally partnered to ACI spokes on the rear however.
We do not use DT or Pillar spokes. We tried the Pillar PSR-1420 X-Tra and found them a poor copy of Sapim CX-Ray - the few wheels we built with them all failed prematurely. Also, we find ACI more reliable than DT Competition at a similar weight.