Thanks for the input as usual. I've got a friend in a tight bind for cash. She's getting rid of cable service and wants to go back to over-the-air for a year or so. I'm trying to get her the best bang for the buck without sacrificing reception but as I've learned here, it's pretty much trial and error. I think we'll go for non-amp first.
The one thing I like better about my Philips antenna is that the amp is variable. There are ten settings, starting from practically no amplification, to full power. I have that one set up in my kitchen, right by a window, facing northeast. (The transmission towers are southwest of here, so I'm essentially pulling in reception on that antenna through my home, through an internal wall, and out the back sidewall of the building.) The amp is at level 9 for best reception.