That's a really difficult question to get a good answer. The reason is that people become prejudiced toward the scanners they own. You can only reasonably compare radios you currently own or have recently owned and used them on the same set of signals in the same area. For instance, I rate the Uniden 785 above anything I own or have ever owned. The 780 is a close second - on some signals in some frequency ranges. That's why I own five 785s. But not even all radios of the same model have identical sensitivity. Two of my 785s can run circles around the other three and clearly hear signals where the others don't - and these are on the same antenna being fed through an active multicoupler. I've had a Uniden 796 sitting right here on that same antenna and it couldn't hear what my 785s do. For all I know it could have been a badly adjusted 796 because other people swear by them. The 396 is not a fair comparison because it's a handheld but I know of at least one 396 that was dragged around this area specifically trying to hear MilAir and it was practically deaf. I've also had the Radio Shack PRO-96 and 2096 hooked to this same antenna and the 2096 was awful and the 96 did a fine job. All of that is to say that getting a good answer to your question is next to impossible - except perhaps from someone that owns all the newer Radio Shack and Uniden scanners and uses them in the same location against the same set of signals. You could always simply compare sensitivity numbers on various freq ranges published by the manufacturers for each of their models to make your comparison - if that really means anything. Finally, yes, a radio can be fine tuned for better sensitivity but finding someone to do it is where you run into a problem. Sorry for being so long-winded, as usual.
