Here's a bit of an update for Smugmug ...
They are still using Adobe Flash Player for the gallery slideshows which is problematic for anyone using a wide gamut monitor calibrated to full gamut. Even if you are using a fully color managed browser, the images displayed by Adobe Flash Player are not color managed. This results in the images being overly saturated (especially reds) and contrasty.
I know that Zen had the same problem awhile back (because they also used Adobe Flash Player), and have no idea if they reconfigured things to correct the issue. I only know that Smugmug has not.
Smugmug has worked well for me, but they are long overdue for a major overhaul. If I were starting over today I seriously look at Zenfolio.