I normally hate posts like this since everyone's situation/opinion is different but... I just sold my 396T since the county I live in is now running P25 phase 2. I'm on the fence whether the SDS100 would be a good buy, or overkill. I was never a die hard user of the 396T, even less lately but that's partially due to the compatibility issue. Before that I enjoyed seeing what could be heard nearby, and it seems like a fun side hobby that I don't want to fully give up yet.
If I'm reading the database correctly, it does look like the Prince William VA system uses simulcast - which I'm reading is a major upside of the SDS100, otherwise I'd be looking more seriously at the 436HP. Anyway, I'd appreciate hearing any input.