I was also a PD user for several years, and at the time I found the customization features awesome. But the more I used it, the more I wanted to continue to tweak and customize even further - and eventually found myself too constrained.
I came across mention of Opus after reading some competitive reviews of file managers, and the author also called out the price tag as an inhibitor - but disclaimed it by saying it was hands down the most powerful and feature rich file manager out there for Windows.
Even still - I also still found the price tag a bit heavy when I looked further into Opus, and I evaled it for like ~6 months in order to learn it well enough that spending the money became a no-brainer. The hardest part for me to get into that state of mind was the steep learning curve at the time. This forum was rather small compared to the number of users now frequenting it, but now - between really great tutorials (some even by other 'users' posted on their own websites - check out playfuls (Andy) guide) and an active user community always willing to help answer questions, it's much easier for new users to get productive than it used to be, with GPSoft putting tons of effort into refining the manual as well.
Over 10 years later - I have happily paid for all major upgrades since my first purchase, and consider it to be part of my most useful computing investment. Calculating a 'return on investment' when it comes to the time saved over the span of over a decade vs how much $$ I actually paid for the software between versions and additional licenses would be really tough. But I'm confident that even with LOTS of time spent actually doing all the customization (alot of it for ~other ppl than just myself), that I've gotten alot of value out of every dollar and minute spent with Opus. Customizing it has become a bit of a hobby for some of us .
You got your answer, but I'd love to call your attention to folder aliases as well. I get the most out of Opus when using both keyboard AND mouse. So I have tons of toolbars and buttons and menu's with tons of buttons... but sometimes, for REALLY frequently used folders, I either save those folders all to open in the lister layout (term used for a saved Opus window with certain toolbars and folders already opened) that loads when I double-click on the program shortcut or the desktop background - AND/OR - I have various shorthand folder aliases that point to folders I goto often. What's cool about folder aliases is that with focus on the file list, you can just hit the forward slash (/) key, then start typing in a folder alias name. You get auto-complete suggestions when you have multiple aliases that start with the same characters, but even without that you can just type partial names and hit enter and you're in your folder! Presto...
Anyhow, if you end up building large collections of folder shortcut buttons like I did, sometimes having a quick direct way to get to some of them is a great add-on to the convenience of creating lots of toolbar buttons to open folders you work in alot.