It is the a-symm I don't quite get for our boats, since it doesn't work on a dead run.
It...mostly doesn't work on a dead run.
I chose an asym for single-handing. It works great for what *I* do (your mileage may vary, contents may have settled during shipping...) Mostly what I wanted was a sail I could use to get down the Sound when it is too light to jib-reach, but not so light that the engine is the only option.
I bought a light (basically 1/2-oz) "A2", which is a light-air running shape. it really shines between about 110-150 degrees apparent wind - higher than that gets a little tight, lower than that and it gets blanketed behind the main (**). But in that range it is a sweet sail and works great.
Yeah, it doesn't go DDW very well. But it's not hard to sail 30-degrees high off DDW, get across the Sound, then gibe and go 30-degrees off DDW the other way. I did this all the way down the Sound on the way back from the Rendezvous - very pleasant day.
(**) It *can* go DDW, if that's what I really need to do. The few times I've tried it, Ive tightened the halyard so the luff is firm, then gibed the main. I end up having a nice wing-and-wing configuration with a light 165% sail rather than a heavier 120% jib. No pole needed (so far) - with the main out of the way it is more than light enough to hold its shape. But it's more sensitive to steering - unlike poling out a jib, it won't stay out there if I get sloppy and head up enough to make the leech collapse.
All of that is, as I mentioned, good for what I do, which is mostly cruising the Sound in moderate conditions. Different needs come into play when crossing oceans.
The one other thing I'd note is that, for short-handed, the rigging required for an asym is a big benefit. With a symmetrical kite, you've got a pole, a foreguy, a topping lift, a sheet, an afterguy, perhaps lazy-sheets and lazy-guys to do gibes.... and a gibe involves disconnecting the pole from the old-guy, swinging/lowering it through the foretriangle with adjustments to the topping lift, connecting it to the new guy and re-raising the pole. Lots of stuff to "do", some of which requires trips to the bow.
The asym has a halyard, a tack-line and a sheet. That's it. I raise mine in an ATN sleeve, then can do the rest from the cockpit (raise the sock, adjust the tackline and sheet). A gibe involves releasing the old sheet, steering DDW with the asym billowing in front of the boat, then sheeting it in on the new board with the new sheet. Much less work, and, can all be done from the cockpit. If needed, I can even douse the kite (into its sock), gibe, then raise the sock to fly the kite on the new gibe - although that isn't as "clean" an approach, because the halyard ends up passing inside the headstay instead of around the front.
Anyway... just two cents worth. Yes, a symmetrical kite is a great weapon for going DDW. But an asym - especially for short-handed sailing - can have some advantages. And sailing 30 degrees high to make it work isn't necessarily a deal-breaker for me.
Bruce