A signal strength meter??? You are joking, right? There's a good reason why old timers sometimes referred to s meters as eStimate meters...
Anyway, I have the 396. The SMA connector (and yes, a SMA/BNC plug is provided) causes very little loss.
You can start doing your homework by comparing the digital trunktrackers with the list of features you want. Lots of folks seem to think the GRE scanners are better in the digital audio recovery, but the downside is that the front end is a tad too hot, and sometimes can overload. The 396's front end, to me at least, is fine - and I live in an urban area. An occasional squawk from a pager, nothing too bad. I use it mostly mobile with an Austin Spectra and travel next to a rather large tower with all sorts of antennas on it.
Anyway this wiki article lists all the digital trunktrackers - note that anything underlined or in blue is a link. Click on the model of interest and you'll be taken to the appropriate article
http://wiki.radioreference.com/index.php/Category:Digital_Scanners
73 Mike