What do you like best about the product?

I’ve been using HAProxy since version ~1.7, and it remains the only load balancer I can confidently recommend. The flexibility it offers is remarkable - from simple conditions to using Lua scripts, to shape the traffic exactly how you need.
It is easy to integrate and combined with automation software (like Ansible) you can deploy a fully reliable environment, essentially creating a turnkey solution ready for clients.
Project is well maintained with long support periods and upgrades can be performed in-place without disrupting traffic flow.

What do you dislike about the product?

Some of the tooling around HAProxy - like halog is not well documented. Only HAProxy 3+ support JSON logs.

What problems is the product solving and how is that benefiting you?

Load balancing the traffic to hundreds of machines with multiple different web services.