I guess things are changing, just my own personal opition, but this is one item I'd never order on line.
I've only installed a few hundred windows and would personally only deal with someone local so if and when there's an issue with the window I'm not having to deal with there expecting me to ship it back at my cost to check it out before shipping out a new window.
In the past any of the three different company's I was dealing with would send someone out to my job site to look at it and if they agreed it was a defect a new one would be shipped at no cost, and several times they even sent someone to install at at there expence.