Personally, I prefer to do it myself. I don't want anyone else's dirt in my house.
I have used Dalworth ( I did not like that they send independent contractors with vans with no name to my house.... I didn't know who was showing up when they knocked on my door) , Stanley Steemer (good job, smells nice but they want to get finished FAST and move on ) and Kiwi (not into the dry method they use, I think it is a waste) in the past but I always fall back on doing it myself.
I have a Bissell Pro Heat and I use mine at least once every 3-6 months in heavy traffic areas. I love this machine. It is easy to use, with attachments for steps. I use the Hoover Pet Formula cleaner from home depot for the best cleaning solution. I rinse in hot water and let dry.
We also have 3 dogs so I need to use my cleaner more than families with no pets and such.
I got my cleaner less than $300 at Bed Bath and Beyond with the weekly 20% coupon. Solution is about $25 a gallon at Home Depot.