As far as tuning & picture quality, my limited experience & from what I've read: they're all pretty much the same.
If he has a need for some specific features, then it can get more complicated:
wiki: CECB comparison chart
Analog pass through-- Feb 17 might move. Low power stations have always had an indeterminate date.
Manual channel add-- tv stations from opposite directions?
Program guide - now/next ; one day ; one weekend ; one week
Also, they all initially are energy star timer on. After the boxes are hooked up, and scanned for channels, go into setup and adjust that setting. Otherwise, they'll turn off every few hours.