Weighing in:
I have a pair of BCT-15Xs in addition to a lot of other analog and digital-capable stuff. RF-wise, the 15X works well - but it isn't my first choice for a weak-signal analog analysis unit. That nod would go to one of several R-7000s in the lineup. My main gripe is that only the BCT-15 and not the "X" model are supported under TrunkStar Elite - which is a package I'm considering buying. My 996XTs (as well as the 996P2) are supported, however. Go figure.
One of my 15Xs has a discriminator tap and I'm going to mod the other the next time I have that side of the monitoring post powered off. Thoughts are to use them with FreeScan to search air-band frequencies, or run the pair of them with trunking decode and DSDecode, PDW and similar utilities. Would I buy them again if I had to? Yes.
Another pair of analog scanners I own are Pro-2006. OS-456 Lite boards were obtained many years ago and I just got around to getting the second of two 2006s to receive these. They compare favorably to the OptoCom (two in use here) and the Pro-2035 (one currently), all of which compare favorably to the -15X. I still go back to the Icoms for digging the very weak stuff out of the noise, but the rest of the GRE and later Uniden gear definitely merit their spots on the shelves.
Something to consider about amateur rigs used for scanning: In my experience, many of their BPF responses tend to favor the amateur bands +/- a couple megahertz for MARS usage. A couple I own which receive from 136-174 (for example) go practically deaf at 160MHz. The type of front end has a lot to do with this - if the rig in question employs a helical resonator setup, it's going to have a very narrow response. Wider front ends invite intermod, though.
...Fred...