Heroku or Amazon to host a backend Rails JSON API? Which should I use?

The answer to this no doubt lies in answering exactly what I need. The thing is... I don't really know.

The criteria for my choice will be price. Whatever is cheapest, unless both are so closely similar and the every so slightly more expensive one is a much better service.

I'm creating an iOS application, and have a Rails backend JSON API that serves my app.

I have a Post/Comment style app. I don't store any images, just text throughout various tables, etc. I shouldn't need much data with no images, and the fact that I will be purging old data (old posts / comments that are no longer relevant are just deleted).

I need a scheduler, likely daily, but guaranteed no more frequent (hourly etc not needed). So I need to run cron tasks daily.

My application does have a user sign-in. Sign-up and you can post and comment, otherwise you can only view. Does that mean I'm going to need an SSL endpoint, or is that not necessary?

Other than that I'm just serving GETting/POSTing data. I don't need anything else that I can think of. As a beginner, am I possibly overlooking anything?

Which service should I go with given the above. This is my first iOS app, and Rails backend (first time working with either), and first time deploying anything to either service, so I'm looking for some advice in this area.

Thanks!