They're awesome, and I need one in a caliber a bit more common than .455.
The double-action slows you down enough that the sight picture always has enough time to settle down. Single-action autos, I find, are quicker to touch off, and the temptation to rush and fuck up is greater. Consequently, for big targets close up (plate rack at 10 yards), the gun practically shoots itself, so long as the shooter is paying attention to the sights. Plate 5 (second in from right) gives me consistent trouble with the Webley for some reason. The same phenomenon seems to happen with the small, distance rack for other people as well - a particular index doesn't want to work consistently; it's happened with IDPA champions, even.
That revolvers shoot themselves was confirmed by putting 32 rounds through a friend's recently acquired Smith & Wesson model 627, which is pure distilled awesome. With powder-puff .357 loads and wood grips, it's absurdly easy to shoot. I'd wondered what the fuss was with gold bead front sights. They seem to work a lot like fiber, except they don't drop out in low light. Fine aim point in the middle of the front leaf, with a traditional picture if you want it. Good set-up. Also, don't go cheap on moon clips. The ones that come with it are utter shit. It's impossible to get the bloody things in the chamber when the rounds flop about excessively. The $5 a hit (!) aftermarket ones make loading a lot simpler.
On the other end of the scale, using a SIG/Hämmerli Trailside on the rack is blatant cheating (we have a sensitive rack, so they go down with a hit on the top half of the plate). When the trigger is like a mouse click, the shots look themselves off effortlessly. Now to get the 226 to shoot like that...