I guess my question is "Will the BCT15X pickup channels that the BCT8 does not?" I know the BCT15X has gps scanning and 9000 channel capability. I do like the headset option on the BCT15X.
You can easily see the differences in the Wiki:
BCT15X
BCT8
While there are a number of differences in frequency coverage listed, the most noticable is that the 15X covers the military aircraft band; the BCT8 does not.
Also, there's a bigger difference than just "more channels" in the BCT15X.
The BCT8 has five banks, 50 channels, and you can enter 50 tallk groups (for a trunked system) in each bank. So that's your limit- five trunked radio systems, no more than 50 TGID's for any one of them. To get more talkgroups on a given system, such as the analog TxWarn (not the digital, since neither of these scanners is digital), you'd have to use a second or third bank, programmed for the same system.
For the BCT15X, while you have 9000 'channels' to work with (frequencies or talkgroups), you can have up to 500 trunked systems, and enter up to 500 talkgroup ID's for a system.
If the BCT15X is anywhere within waiving distance of the cost of the BCT8 (and it usually is), the choice would be easy for me- go with the 15X. Hopefully, you can return the BCT8, without taking a big hit.
Long term, though, you will need a digital scanner, as that's where the systems that interest you are headed- digital.