Thanks for the answer Frederick, that sounds good. I might give W3TC another go if increasing user amounts on our site prompt us to look for speed optimization. While using W3TC some two years ago I ran into a sitewide white screen of death that required FTP removal of the plugin to resolve. Hopefully during these two years the plugin has learned to avoid or gracefully overcome more of these situations.
Right now I'm pretty happy with WPSC. The only issues so far are the admin bar's Delete Cache button that sometimes shows and sometimes doesn't, possibly due to a plugin conflict, and the fact that garbage collection stopped completely when set to run first at 00:00 and then hourly. It runs like a clock now when it's set to run at a specified interval (300 seconds). Site is fast and the plugin causes no extra maintenance besides having to keep a browser tab open displaying the plugin's clear cache option while developing. Minifying and combining the .js and .css files could make things faster especially for mobile connections, but as setting that up takes time and can lead to unexpected problems, it's not yet among the immediate priorities.
Ideally I'd just add a Minify solution to my current setup and manually choose for it to combine the files that are not under development. However, WP Minify has several unsolved critical issues raised during the last month and the other plugin I know of, Minify, is so new that it has only one rating and an unsolved critical issue. W3TC is tried and tested, but is quite a mammoth to install just for the Minify.