...or should I have picked one up?
Hey Holmz...you already know you should have picked one up if you had the opportunity to do so, they were on the cheap and that's the reason for the cataclysmic proportions of that whole Festool debacle...oh my head hurts just thinking about it.
To answer your question, the PRO 5 is:
a fantastic $100 sander...it's also a good $200 sander, but it's not in the same class as the ETS EC 125. That sander is a standout, similar to your Mirka.
The Pro 5 will live its life NOT
as a trailer queen, but as a viable finish sander with its 2mm orbit, while the ETS EC will continue to be my main go-to sander with its 3mm orbit.
I already own an RO 125, but I pretty much position that sander as the equivalent to a belt sander. The convenience in the Rotex mode is extremely nice, however the weight and bulk is not really conducive for fine finishing. It can be accomplished but at a cost.
My Milwaukee belt sander however...made in the USA...is a plywood/hardwood eating machine. It chews up wood and stainless at the same rate. It knows no master and acquiesces to no one..its really too bad that Milwaukee no longer makes this sander as it could be refined into being a really strong sanding machine if they'd have offered a sanding platen like the Festool.