I'm trying to evaluate the best way to be handling image attachments into the future.
I've been really happy with image_attach so far, as it does exactly what I want.
But it doesn't do that in a CCK-happy way, so the extra options for node construction aren't there. Neither does it allow multiple attachments.
cck-imagefield however seems to be pretty limited so far, and according to it's gigantic wishlist, seems lacking a bunch of functionality that image.module already solved. Thumbnails, existing image re-use, granular permissions, custom filenames using tokens and more.
The major difference between these two approaches is the desire to treat attached images as full nodes (image_attach) or to try and avoid doing that (imagefield)
Many of the extensions and extra options that folk want for imagefield are HARD because of that inbuilt limitation.
Sitting off to one side is asset - which is in its own world of file management, and although the management wizard interface is wonderful, it doesn't treat its items like either nodes or fields, so it doesn't play nicely with either approach.