Try them then decide
I have a 436HP on the way and my plan is to purchase ARC 536 to go with the Sentinal software. My question is will I find the ease of use with it as compared to what I have already been doing with FreeScan and my 996XT. I did not find it to be very difficult to pull directly what I wanted from the RR database and create my own scan lists in the past. Can someone let me know how similar the experience will be? I do have a premium subscription to RR as well.
Going back to your original question. My advice would be to download the trial versions of ARC536 and Proscan (after you get your scanner, since the 30 day clock starts when you download) and then try all three packages and see which one(s) you prefer.
This is definitely a YMMV (Your Mileage May Vary) thing. Some people are comfortable just using Sentinal, and you still need to have it to update the scanner's firmware and the onboard database. It also comes free with the scanner, which is a plus.
Personally, I don't use the database at all, and prefer to create favorites lists based on RR downloads, just like I do with all my other scanners. So I do all my programming with ARC536. The one exception is when I want to delete a number of favorites lists and start over; I use Sentinal for that since I haven't figured out how to do it with ARC536. But that's just how *I* do it; not saying that will work best for you or anyone else.
I also prefer to use virtual control on my scanners, and I ended up buying a copy of Proscan as well, because I found the VC in ARC536 to be lacking. But Proscan currently doesn't support programming the 436/536, although the author has indicated he may be adding that in the future. That was what kept me from buying Proscan instead of ARC536 in the first place. Proscan also has the advantage that it works with a number of other Uniden scanners too.
So again, my recommendation would be to download the trial versions of ARC536 and Proscan and try all three packages, then decide what works best for you. If that turns out to be Sentinal, great ... you've saved yourself some bucks.