Personally, and as the owner of a new build SM300, that would get my vote. They are such a pleasing design in the metal, just retro enough, the right size and also very wearable with long or short sleeves. A lot of people comment on my SM300. The bracelet is easy to remove (I have an oyster) and they work really well on a black NATO as well.
The IWC is a lovely movement, true, but it's a little too ordinary in appearance for my tastes, and I don't like the arabic numerals on that dial. They seem like an afterthought.
Just to whet your appetite, here's a link to the original build thread for the watch which is now mine.
http://forum.tz-uk.com/showthread.ph...My-SM300-Build