I have and use both. I love the simplicity and user experience of JRiver but hate the constant "buy it again" upgrades. I stopped updating it and just use it. I love the flexibility and tweakability of Foobar. It's kind of like comparing iOS and Android, or Windows and Linux. I've found as I get older simplicity is trumping out over flexibility. I traded in my Android phone years ago for an iPhone. I find myself using JRiver most often. It just does what I need it to do.
Martin
Martin