The set of wheels I've just finished making have 32 hole rims (Mavic Open Pros) and I've used CX-Rays. Although the aero properties are pretty much irrelevant by the time you're up to 32 spokes, they're light and strong, which is good. But the real reason why I like using CX-Rays is because it's so easy to avoid spoke wind-up when using high spoke tensions by using a spoke holding tool at the same time as a spoke key. YMMV, but in my book the extra cost is justified by the ease of use.
The set of wheels I've just finished making have 32 hole rims (Mavic Open Pros) and I've used CX-Rays. Although the aero properties are pretty much irrelevant by the time you're up to 32 spokes, they're light and strong, which is good. But the real reason why I like using CX-Rays is because it's so easy to avoid spoke wind-up when using high spoke tensions by using a spoke holding tool at the same time as a spoke key. YMMV, but in my book the extra cost is justified by the ease of use.
I also think they look nice...