For what it's worth I have had both scanners, I've always been a Uniden man for consumer grade scanners since time began, every once in a while I'd grab a Radio Shack scanner if one caught my eye or through the recommendation of a friend in the hobby. I'm an old-timer & the BC-15 was an excellent scanner with specs close to some of my high end scanning recievers, however the instruction manual was unbelievably complex to read & understand, not to mention the revelation that you had go on different websites to activate some advanced features on the scanner & purchase additional items to activate other advanced features which really angered me since I couldn't even deal with trunked systems at the time, I mean just forget GPS, signal stalkers, etc. etc. etc. The PSR-400 was a total disappointment as it was completely deaf on civil aviation 118.0 MHz to 136.975 MHz & adjacent channel rejection was almost totally nonexistant, so much for that. If I was savvy to the sytems these new scanners receive nowadays I would pick the BC-15 so here is my recommendation to you before making any purchase, read the user manuals for both scanners this way you can make an informed decision. The manuals are available for viewing free on their respective websites.
unidenamerica.com
GRE America, Inc. - grecom scanner receiver, lcd modules, spread spectrum radio, wireless bridge, scanner antenna, scanner pre-amps.
You can view free the instruction manuals that AlabamaRS recommended for the RS PRO-106 & the PRO-197 on:
www.radioshack.com
Good luck.
FLRAILMAN