They aren't technically a private service. They're more akin to a public utility model. The operations aspect, ie management, billing and so on, are contracted to private parties, but the agency itself is not private. They are the sole 911 provider for most of Tarrant County, which is mainly Fort Worth, and a bunch of the contract cities.
Their protocols are up to snuff, they have CPAP, field termination, and RSI. They actually have several levels of Paramedic, and each level has a slightly expanded scope. They have also started a Community / Advanced Care Paramedic program.
They are VERY busy... a 12hour truck gets between 8-16 calls a shift, on average. They use SSM, so unless you're one of the couple 24 hours trucks, you'll be posting in what little downtime you have. Their trucks are Medic/Basic, with a couple of Medic/Intermediate, and Medic/Medic.
From my ride time with them as an EMT and Medic student, and knowing people who work / worked for them, they are a good agency. They have a moderate turnover just because of how busy they are, and people are more wanting to get on with the local FDs, but that doesn't necessarily make them bad.
They are one of my top 3 agencies to get on with, but part of their hiring process is the "Strongly Agree / Strongly Disagree" type test on their website, and apparently I suck at that test and am labeled as crazy every time I take it?