I purchased the Orange/Black Core and replaced the band with the lugged black band (aka Military style). I've had it for a couple weeks now and this bad boy does the job! The barometer seems to maintain +/- 1% accuracy once the correct sea-level pressure is set. Haven't had a chance to test the altimeter yet, but I'm sure it'll follow suit since it's somewhat dependent on the atm. pressure. I used to have an Observer and the Core is much lighter due to the materials used. The mineral glass seems thick, but I'm not sure how scratch resistant it is. It may look like a toy watch at first, but the functions speak for themselves. The menu is intuitive and I really didn't use the manual much. Only thing that could improve on this watch is the brightness/contrast of the display. Other than that, I would recommend this watch to any outdoor enthusiast.