That's simply their policy and way of doing business. Probably the main market they try to target is not interested in that. I know I don't care much for phone support.
Will it be noticeable?
There will be a difference but chances are no one will notice it while browsing sites. How many times were you able to make the difference between US hosted sites and Europe hosted ones unless you were actively trying to make a comparison?
Do they host any "big" sites?
If I had for example a page full of photos (say 30), where you could click on each one to see it fullscreen, would it take longer to load from a US server than a European one? Would clients notice the difference?
I am living in Europe, and using Site5 myself; and since I am a bit of a night-owl I don't see any harm in the time difference...
Also I don't notice any slowness due to distance. I'd say it's more important that the host has plenty of bandwidth connecting their server park to the internet backbone.