Rolex watches were made famous by their oyster cases & COSC rating. Then they became popular, then they began producing huge numbers of watches available in hundreds if not thousands of retailers world wide. Their high resale value is perhaps only surpassed by Patek & then only when looking at older pieces. Rolex is the most well known watch brand in the world & this has created their value. Does this make for a better watch? Is a Chevy a better automobile than a BMW who produces far fewer pieces? The analagy isn't fair but it is true that volume creates market awareness & high resale when availability of especially a few models remains scarce. Look what the corvette has done for chevy.
UN is probably the greatest innovator in modern times & I can speak volumes for their support (used only when I needed to get a new strap on my Marine Diver when in horror I cut it too short).
Both brands are spectacular & will give years of enjoyment on your wrist. For me the ? is do I want a watch that only few will recognize, but as the wearer I will always feel its quality & know its long history of innovation. or do I want a watch that speaks volumes of my status in life for all to recognize (hopefully not as a fake!).
I wear my UN & don't mind a bit when somone looks in curiosity at my beautiful watch which they never heard of.