with modern designs moving more and more towards very advanced SMPS, and ditching the traditional LDO and linear regulators, it's very hard to gain insight from an analog scope these days. Scopes have sort of transcended their traditional uses and limitations.
in terms of reliability, modern SMPS and POL systems have become reliable, to the point of not really having to question them. however these systems require more and more bulk caps, and if the caps used are dodgy, that is a potentially HUGE problem.
I don't think there is any real compromise in quality in Rigol PSU's. They are as good as anything out there.
On the front of reliability, an older scope is going to be impossible to repair (in some situations). The only reason I can see for using anything (other than a good modern DSO/MSO) is for characterizing noise in highly critical power supplies.
If the work you do doesn't require such tools, I am sure it could benefit from some other modern equivalents. For example.....audio gear. Could you imagine going back to using older THD and RTA? With modern spectral analysis and harmonic analysis tools, it's hardly possible to imagine going back to less parametric analysis.
It's nice to have older gear for very simple and specific things, but the pace of modern consumer technology just doesn't allow for the "traditional" toolset. Believe me I don't think that is necessarily a good thing, but it is reality.
In a production environment, I just don't see how it's possible to spend the time to maintain old dinosaurs. Example....i owned a recording studio for many years....and people used to bring in all kinds of whacky "vintage" gear. Old altec compressors etc.....they had the illusion that they were somehow "better". That concept quickly changed when they spent all of their session time tracking down the radio signal making it's way through the piss poor designs of the older gear.
Example, i have a nice "mint" Pultec EQP1A (uber lusty gear-slut vintage EQ).....although it's fully rehabbed and meets spec....my modern clone (EAR822) simply decimates it, in terms of performance and noise floor. Not to mention I can actually source the parts to fix it. People get caught up in ridiculous notions that something from an era gone by is somehow "better".
Don't mean to take it off topic, but I think these are valid observations, that can easily be applied to any piece of "gear". There are most certainly reliable high performance tools being sold as new...