This is my experience, too. Heroku didn’t stay competitive price-wise with alternatives. And scaling even slightly from the basic dynos quadrupled (or whatever) the price.
Feature and experience-wise, we were always really happy with heroku.
I don’t know if this fits with the “salesforce purchased and let stagnate” narrative that nearly everyone here is pushing.
Heroku got a lot of attention and funding within Salesforce at least for the first few years - they grew from about $1M in ARR when they got acquired, and I think they peaked at around $200M (second hand - so I don't know if part of that was funny-money revenue allocated from Enterprise agreements.)
Feature and experience-wise, we were always really happy with heroku.
I don’t know if this fits with the “salesforce purchased and let stagnate” narrative that nearly everyone here is pushing.