re: Solid Queue
That Redis is fast is certainly a benefit to using e.g. Sidekiq, but it's not really the main reason you want your jobs in Redis. The reason is that you don't want your jobs in the same database as your operational data.
I don't think 37signals are making anything up, but just remember that their tech leadership has extremely limited experience and that dismissing the collective wisdom built on decades of experience is not something to do lightly.