I've been on Rails 8 for a few months on a side project. Here's what I actually use day to day, versus what I expected to use.

Used constantly:

• Solid Queue for background jobs
• Solid Cache (one less service to run)
• bin/setup style scripts

Barely used:

• Kamal (great, but I deploy to one box)
• Propshaft (nice, still learning the edges)

My take: the "no extra services" direction is the real win. A side project that runs on one box with a database and a queue in the same database is exactly what I want at 2am.

I'm still slowly reading SQLite internals. The more I learn about storage, the more I appreciate how much Rails hides.