What should matter most when judging an exposed mechanical movement?

Finishing first, layout second. You can have a great layout with sharp edges and it still looks cheap.

Layout matters more to me than most people admit.A skeleton watch lives or dies by how the movement is arranged. If the gear train is just a straight line with no thought to visual balance, it doesn't matter how well it's finished. I've seen high-end pieces with beautiful anglage that still look dead because the architecture is boring.

What do you mean by dead?

No depth, no sense of layers. Everything sits on one plane and your eye has nowhere to travel. Good skeletonization gives you bridges at different heights, negative space that actually reads as intentional, and a sense of looking into something rather than through it ngl.

I'd argue reliability and serviceability should be near the top. An exposed movement is still a movement. If it's a nightmare to service or the skeletonization weakened the bridges, you've got a pretty object that's going to be a headache. I've passed on watches because my watchmaker took one look and said no thanks.

You ask. If they don't know, that tells You something. Beyond that, look at the bridges. If the skeletonization has left them very thin in structural areas, that's a red flag. Also check whether the manufacturer has a service network that will actually touch it.

Accuracy is the last thing I care about in a skeleton. If I wanted accuracy I'd buy a quartz. This is about the visual experience.

That's a bit extreme. You can have both. Plenty of skeletonized movements keep decent rate. I think writing off accuracy entirely is a mistake.

Decent, sure. But it's not what I'm judging the watch on.

Consistency of finishing across all the visible surfaces. It's easy to do a nice job on the top of the bridges. Look at the edges, the countersinks, the jewels. If the underside of a bridge looks like it was done by a different Hand than the top, that's a problem.

They should be polished and even. If they're rough or off-center, it suggests the finishing was rushed or done without much care. Same with jewel settings. A well-executed skeleton will have those details treated as part of the overall composition rather than an afterthought.

All of this assumes you can actually see the movement well in person. Photos lie. Lighting in a store is designed to make everything sparkle. I've bought skeleton watches that looked incredible in the case and flat on my wrist at home.

This is why I always ask to see it near a window.