I don't know too much about Dallas, but I could write a bit on Oklahoma.
Oklahoma EMS can be summed up in four letters: EMSA. EMSA is one of the original public-utility models, and today takes the form of a partnership between the EMSA trust and AMR. They cover both OKC and Tulsa, and select suburbs of both. It is a fully-ALS service that is nearly exclusively Paramedic/Basic. They utilize dynamic posting/System Status Management and are fairly busy, units averaged 7-10 calls per day when I left last fall in OKC. Their protocols are middle-of-the-road and can be found at ww.okctulomd.com. They have decent equipment- electronic Impact 731 vents, Lifepack 15, power cots, phasing in powerloads, all F450s. Zoll Rescuenet EPCR. It is a non-transporting ALS fire system in both OKC and Tulsa. Edmond, Yukon and Mustang are also ALS. Bethany, Nichols Hills, and the eastern towns are BLS, some volunteer. EMSA owns transports and all medical.
EMSA hypothetically is responsible for ALL ambulance operations in its cachement area, inclusove of transfers and such. In practice, all 911s and a substantial number of interfacility transfers (inclusive of returns to nursing homes, residences, LTACs) are performed by EMSA, while dialysis and wait-and-returns are handled by other privates (OCCT, Guardian/EMS Plus, Miller EMS, Samaritan, Mercy). Level Zero can affect these but AMR leadership and EMSA love transfer dollars, so they happen.
Pay is somewhat dependant on experience as a paramedic. If I recall correctly, brand-new Step 1 paramedics were entering at 14.21/hour last year, while Step 2 medics like myself (4+ years of experience) were at 15.82 an hour. The schedule is a base 48, all hours paid, with OT after 40 hours. Overtime availability varies but is fairly consistent if you really want it. The benefits are standard AMR- a 401k with 4% match if I recall correctly, Aetna insurance that was reasonable, etc. I took home approximately $1100 per check as a full-timer at 15.82 an hour after taxes, without additional overtime (only 48 hours a week). You are looking at about $39,000 to $41,000 gross a year as a paramedic under most reasonable standards at EMSA. With that being said, Oklahoma has a weird income tax and it is highly recommended you overpay approximately $50 per check on your state taxes.
Pros: Protocols are fairly decent, and mirror the Oklahoma state protocols almost exactly; in fact, the state protocol team and EMSA OMD are essentially one and the same. The equipment is good, and you are functionally pretty autonomous. You will see a very diverse population and run a lot of calls. Every call is ALS-teched, so you will write all reports and tech all patients, you will get a lot of experience. The response areas in both OKC and Tulsa go urban to rural, and you will run everything from wildfires to tornadoes to nursing homes in the same shift. Lots of variety. Generally good PD and FD interaction if you're not a ****.
Neutral: AMR. They're a faceless, for-profit private, but they are kept in line by the contract and local leadership is actually really good. Joanne McNeil is the administrative manager (405)297-7879 and is a fantastic POC. Your coworkers run the spectrum from comprehensive to minimalistic in treatment mentalities. Dynamic posting means you get variety, but also might not ever stop driving. Checks clear. Supplies and rigs are stocked by materials department. Broken rigs can usually be exchanged. OKC has an optional union.
Cons (opinion): OMD and leadership will not support your decisions or your clinical actions if it even looks different than a hospital's expectations, regardless of protocol, intent or outcome. They don't want to hear rationale, they want adherance to the protocol. DO NOT COLOR OVER THE LINES! EMSA's ideal is not a clinician, it is a protocol-driven technician. Do not exercise creativity, develop a reputation as a free thinker or an aggressive medic, and do NOT challenge the powers-that-be. You'll lose. Also, the EMSA ideal is minimal use of pain meds, if my anecdotal observations were accurate. You can give them, but it seemed that the backsided OMD message was very....conservative. OKC can be very cliquish. The schedule and SSM can get very old, very fast. New hires are generally stranded on night shift for a year or so.
In the state, EMSA is upper-tier. Broadly, there are several decent counties in Southern, Central and Eastern Oklahoma. Muscogee, McClain-Grady County are supposed to be decent. Ardmore is serviced by SOAS, a nonprofit that pays approximately 40k a year. Pottawamie County Shawnee is covered by REACT- a nonprofit, at about 35k a year. Stillwater is covered by Lifenet, a for-profit private, approximately 36k a year with a mixed reputation. Eastern Oklahoma is served primarily by Pafford EMS in the larger towns (McAlester/Pittsburg County, LaFlore County, Sallisaw, Claremore/Rogers County); Pafford is probably the most clinically-aggressive in the state but pay is lower and hours are longer (most Pafford employees work a base-72 and are at $11-13 an hour, but take home 43-46k a year as medics). Lawton is covered by Kirk's and Comanche County Hospital, they both kind of suck for pay and conditions but have a thriving knife, drug and gun club. You'll be looking at 32-37k a year. AMR also covers Duncan and Stephens County, but they are both clinically bad and the stepchildren of AMR Wichita Falls and very poorly paid, you'll make 29-32k a year here. Out west, Weatherford and Sayre are covered by Sinor EMS, a horrible for-profit company where you can work 5 24-hour shifts a week, get paid for 13 hours a day and get to experience slavery firsthand. Altus is covered by a similar private service, as is Woodward.