I used Nations once and that experience was fine (although I did notice a problem with some blown highlights in the printing that weren't blown on the original image I sent them. So they did lose some detail in highlights. I considered maybe it was a color gamut problem with the printer.)
I tried to use them again but needed to have the print delivered to an address in Hawaii and I couldn't easily do that myself online. SO... I called their "best customer support" (several times)... and it rang and rang until it went to a recording that basically said "we're too busy... open a ticket on our website".
So I opened a ticket... never got a response, acknowledgement, call... nothing.
So much for "best customer service". <shrug>
I ended up ordering the print from Aluminyze... I've never really had a reason to interact with their customer service, but the order went through fine and the images from them are amazing.