Hey DB, I keep meaning to respond to your PM (is it enough to say that I LOVE UTS?), but life always intrudes, as they say. Anyway, to answer your question, I feel that the ETA 2892 family of movements compares quite favorably to the cal. 39 in terms of accuracy and durability (indeed, I feel that this particular movement compares well with a host of in-house movements, including the venerable 3135 from Rolex). Where it falls short in this instance is in terms of decoration and the mechanics of the GMT complication. For starters, the hour hand isn't quickset on the 2893, and of course GO adds push-button functionality to their caliber, which is incredibly convenient for frequent travellers. Oh, and let's not forget GO's trademark big date complication, which is the best in the business, IMO.
Regards,
Adam
PS - BTW, I feel that the same applies to the ETA 2824, which may not be the most refined movement out there, but has certainly proven itself time and again to be a solid, accurate, dependable and easy to service engine.