It's my home airport and I'm very happy with it. A lot of the complaints come from occasional leisure travelers who are flying with Allegiant and confuse their issues that airline with airport operations as a whole. The TSA backlog happens when Allegiant banks their flights in the summer. So be aware of the departure schedule. And I've never waited more than about 3-4 minutes in the TSA-Pre line.
There's a kiosk outside security, a sandwich place going in airside to replace where Quizno's used to be, and a sit down bar and restaurant with a common kitchen area that serves both land and air side. Though if you've got the time, I'd just stop at Doc's Oyster Bar on the Bayou in Valparaiso on the way to the airport instead. Looks like a dive but the food is good.
It's an airport that's in the middle of some growing pains right now, especially during busier summer months. Passenger count has doubled since Allegiant went into there, and gate expansion is in the works but 2-3 years out. They are playing catch-up to a decent degree (checked bags are now relatively quick to the carousel after I spent 2018 maxing out on Delta's '20 minutes or 2500 miles' bag guarantee) but things are going to get a little crowded until then during summer surge times. Overall though, I still find it very manageable, especially with Pre.
The military and the airlines do a good job of working around each other. My most common Delta delay is a departure hold due to Atlanta ATC request, which is the same thin you'd get flying out of PNS or ECP with that airline.