interesting to see this thread here.
there are several very good threads, all on other forums unfortunately, where donahoe and swayaway actually have a long, drawn out discussion on the pros and cons of their coilover designs.
the basic bottom line is as seth_js already put it...the d/r coilover is probably the best quality, but the saw is the best deal for your $$$.
also, when you get in to rebuildable, adjustable coilovers, they are all very similar inside...whether it's bilstein, king, donahoe, swayaway, fox, kuster, or someone building a coilover to fabtech, allpro, camburg, etc's specifications which is then badged by that reseller with credit given to the manufacturer, except possibly in the case of the fabtech dirt logic c/o which i think is made by fox but not labeled/advertised as such.
it's actually pretty interesting how related all those designs are, because the designers and machinists all worked for one or the other company at one time or another, and switched companies, started their own brand, split, merged, etc...
so really what you're getting now is customer service and minor design changes. saw and donahoe both have excellent customer service and are very, very involved in the forums frequented by the average joe...not necessarily so the other brands. any of the manufacturers could easily, accidentally or intentionally, duplicate the internal functionality of another's coilover, so what you're really discussing is the factory spring rating and valving on the most common offering. offhand i'd say it would be better to get a set of c/o from a reputable reseller who's chosen near-ideal valving than buy a standard c/o off the shelf, for instance the "standard" saw coilover vs the camburg spec. theyre both saw, but one is more closely spec'd to your vehicle. donahoe is the same way, and either manufacturer can build you whatever you need...bypasses, remote reservoirs, longer or shorter shafts, etc...
i have heard of good and bad customer service on king, never heard anything about bilstein's c/s, heard mixed stories about fabtech's quality, and only heard/experienced good customer service and quality with saw and donahoe.
-sean