Southwest doesn't give it to you for free, it's in the fare. I would definitely rather travel Southwest but in my current market (STL) Frontier is by far cheaper. Yes, including all fees. I have had one long delay but I was emailed in advance so didn't even leave home, was a better flight time for me anyway, and they gave me $100 off my next ticket. My ticket that was delayed only cost $100 so that was cool because now I'm throwing in an almost free Vegas trip.
In fact, many times even airlines such as American Airlines are cheaper than Southwest so I'll choose them in order to have an assigned seat. I haven't had a lot of that award winning experience on WN in years anyway.