Here's my experience
I'm am or was looking for hosting for my paysite.
I tested these hosts support #'s on a sunday night around 3-4 am and their sales during biz hours. This is just my experience, not my opinion.
National Net - answered in 1 ring, Got a quote from them within 1 hour of contacting Bill.
Phatservers - first time I called got a fax machine, second time forwarded to VM. Contacted Mike for a quote on a colo, handled within minutes
ISPRIME - after getting through the menu 3 rings. Contacted Denis for a quote got it within an hour.
OC3networks - didnt call support but their sales suck ass. Emailed for prices never got a response, called and left a message no response. Going on a week.
Jupiter - Called sales, left a message with receptionists, Never got a call back. Searched GFY for a contact, contacted Poppy but couldnt get a quote because they are restructuring pricing.

Swiftco.net - Contact Henry for anything you want or need. Excellent host

Webair - never tried
Mojohost - never tried
So far National Net is superior in every way. Ofcourse they cost a little more.