Wealth of add-ons and ease of setup are great. Pushing from code straight to development was a novelty for me when I started off and now with docker support this is even better.
The database handling is superb. I like the way the product has improved over the years with current technology being supported.
I dislike the random nature of the routing algorithm, it could be much smarter. Sometimes a request gets stuck behind a slow request. It is hard to gauge the capacity needed at times due to this.
I hate the 30 second restriction which although it makes sense from their end does not lend itself well to be fully compatible with all open source libraries in our stack. This tends to make customisations a must which is a pain.
Can get very expensive unless you manage dynos well.
Great for small teams and if you need to validate your product.
The main problem is a SaaS platform with global reach.
The main benefit has been the ease with which we can deliver updated code and new features..