Seeking Advice on Choosing a Security System for Large Home

We recently bought a 7,000 sqft home with an existing ADT system. The system is old, and ADT recommended replacing everything. I also received a quote from Vivint, which was less than half the cost of ADT. Finally, I spoke with a local installer, but his price for a Honeywell system was higher than ADT and nearly three times that of Vivint.

I really want active monitoring because we live in a town with an excellent and responsive police and fire department, and the automated calls are important to me. Any advice on choosing the best security system would be greatly appreciated.