Depends on who you ask. I think functionally they are identical with the exception of magnetic exposure in METAS is not part of the ROLEX test. Post late 2015 Rolex are water tested. Rolex is +2/-2 and Metas is 0/+5 seconds a day. You can correctly argue that this is actually identical and the 0/+5 is actually better as its preferred for a watch to run slightly fast. Metas - http://www.fratellowatches.com/omeg...ied-metas-announced-warning-long-opinionated/ New Rolex - http://www.ablogtowatch.com/rolex-extends-stringent-in-house-tests/ Notes on terms and recent history. Master vs METAS the Master rating basically means anti magnetic and COSC. METAS is being slowly rolled out and is limited at this time. Pre late 2015 Superlative from ROLEX just meant COSC certified then retested inside the watch. Since COSC testing was done on bare movements with place holder minute and second hands.
This reminds me a little of a recent article I read about "gourmet" finishing salts and which one is better. Think pink Himalayan rock salt, black Haiwaaen volcanic salt, Fleur de Sel etc, etc. To summerise the article, it makes little, if any, difference which salt your choose as they all taste the same, salty. Go with the one you prefer the look of as this will be the main difference.