Can you expand on your goals?
Will you be using it inside or on the road?
How much will you be traveling with it?
Are you interested in Police/Fire only, or do you want to be able to scan other radio traffic?
It seems like you'll be mainly listening to TxWARN P25 digital. The scanner you selected is probably just as good as any, if not the best, for receiving this system. You probably don't need ProVoice, unless you are going to visit San Antonio a lot. You probably don't need the GPS either. If you want to venture into scanning outside of public safety and TxWARN, DMR can be very interesting. I did a search of FB and Brazoria, and there are a ton of DMR users (
DMR Frequency Finder). It's probably worth getting.
I'm not sure how much of the south Harris county law enforcement is in the clear. Maybe someone in the area will chime in.