"For a cheaper delivery" -- hah, not exactly. burgerto.me is $10, period. Get It Now may or may not be cheaper -- it depends on how far you are and how much you buy.

This is not to say that Get It Now isn't a good service. I just don't think it's as simple as you're saying it is.

I think I prefer the flat rate, but that's just me.

(edited to be slightly less argumentative ;)

On average, for most places in SOMA/Misson/Marina, Get It Now has been cheaper than TaskRabbit.

(This is based on my own experience using both services and by the released average Get It Now has been using in their PR.)

I think you prefer TaskRabbit because you work there. :)

Is Postmates really cheaper?

It depends where you are, but the last time I checked it was about $8 to the Mission and the first delivery is free.

Yes and Postmates is available 16 hours a day, on weekends as well. TaskRabbit operates "business hours on week days" only.