I prefer SMS personally since I do not have reliable data in all locations but the voice/SMS is typically much better. I'm ok with a notification being sent back to the phone via some kind of push for most things but SMS has been great in the past.
I should say that I used to have a SMS setup in conjunction with ActiveHome Pro. In that case I was using Google Voice as the means to communicate since the HA server could simply check the GV account every few seconds for new messages, process the resulting command, and respond as needed.
My primary use is outdoor lights for my dog's kennel. For example, if I go to a sporting event don't get home before 11pm on the weekdays or forget to turn the lights on prior to leaving on weekends, the dogs will be left in the dark. It's probably not an issue, but we do have coyotes that could get bold in the dark. The setup was useful to turn the lights on with a verification that the HA server had done the job. The venue may not have reliable data but SMS always go through. Unfortunately, Google basically killed GV so I'm now looking for an alternative.