Heroku is one of the best known PaaS (Platform as a Service) vendors. It was founded in 2007 (two years before Node.js was first released). Both Heroku and Cyclic offer a similar set of standard basic features.
Heroku is built around a concept of "Dynos". These are lightweight containers that are priced liked servers but have some attributes of on-demand serverless style runtimes with elastic scale up. The downside is that you still pay for idle.
Cyclic is a good alternative to Heroku if you are looking for a modern cloud architecture, serverless hosting infrastructure, easy on-boarding experience, a bursty or inconsistent workload. Or if self-hosting is required (BYO cloud account). Pay for the requests you use, auto-scale from the start.
Here is a breakdown Heroku compared to Cyclic on individual features:
 Heroku free tier discountinued as of 11/28/2022