I replaced two Pella Pro Line windows a few years back that were 16 yrs old. The Pro Line is not the top of the line window (just like one poster said, companies make different grades for the market) so when I looked I got three quotes. I went with the top of the line Pella window as they were less expensive (Anderson was the most expensive)than the other two quotes. I am very happy with the replacements.
This is true...pay close attention to the NFRC and SHGC values...they compare apples to apples on how efficient the windows are. Also, be cautious of those saying to go with to go with a carpenter. Windows are only as good as the installer. You wouldn't take your Porsche to Jiffy Lube.