From one Greene County "newbie" to another, here's my feedback/experience getting back into the hobby.
I too was out of the hobby for a while and, when I got back in a few years ago, decided the BCD436HP was the right radio for me at the time . This was also my introduction to Sentinel software - which comes free with the radio.
There's tons of information regarding Sentinel software on this forum, YouTube, etc., so I won't go into a lot of "how to" detail here but, in summary, it loads on your computer and connects to the Radio Reference database when opened. For a newbie, it has a nice, easy to use, interface for locating, organizing, and downloading to your scanner, the systems you want to listen to using what's called Favorites Lists. It also does a nice job (again, for the novice user) of taking some of the guess work out of how to config your scanner by doing much of it for you. Of course, as you learn more, you can tweak settings to suit your own needs.
As far what scanner for Greene Co? I started with the 436, which I still have, and it's a great scanner. When Greene County migrated to P25 (MOSWIN), and I got a bit more familiar with the 436, I did notice some minor simulcast issues. Based primarily on what I learned from this forum, I took the plunge and got he SDS 200 (also comes with free Sentinel) and absolutely love it. Comparing the 436 and SDS 200 side by side I did determine the SDS did a better job than the 436 in my area. But, again, both are excellent units and Sentinel makes it easy to get either one up and running quickly for someone "re-learning" the hobby.
Hope this helps.
BTW - only a few Tac channels are encrypted and this point in GC. Most other public safety is still in the clear.