I have owned and tried a few pieces of Grado gear over the years. These have managed to remain so far:
The SR 80 - bought them some 20+ years ago. I always liked how open and light they are, both in terms of how they wear and how they sound. I hardly ever listen to them though these days and rather keep them for nostalgia reasons, they are more entry level and have some limitations in accuracy and linearity.
The earpads after some years basically dissolved and crumbled into a nasty black powder everywhere - got them replaced by their local repair service. Prior to that they had already fixed an issue with the internal wiring for the left driver, which basically became loose without any intervention probably due to a production fault, but worked flawlessly ever since.
I recently tried some more of the Prestige series (the newer e models) and basically didn‘t like any, especially when compared to my SR80 which I always preferred - with one exception:
The SR325e - bought that roughly two years ago, and while I wasn‘t too impressed over various headphone amps in my big home rig, I‘m still superimpressed to this day every single time I use them straight out of my iPad Pro with Spotify, can‘t explain which strange and special kind of synergy is going on there, they play so transparent and detailed with a wide soundstage and a beautiful, pretty natural tonal balance across frequencies without too much colouring, just love them in this combo. Although the vintage look is really weird, when I wear them my wife keeps shooting me comments like „is the radio operating?“, „hey Mr. Operator!“, „are you in contact, will they get us out of here?“ and things like that 
So I was pretty annoyed when I yesterday tried to adjust the fit, and the plastic bearing for the right cup broke just like that:
So in my opinion and from my limited experience, product and build quality is an issue.
I had tried the RS1, later the RS1e and the RS2e from the Reference Series, but never warmed to their sonic signature, and their on-ear fit. I had always wanted to spend some time with the PS200e though, the top dog of their Professional Series, but never came to it and realistically don‘t expect that to happen.
As mentioned above and also in the „Got Wood“ thread, Grado also has a renown phono line, of which I own two bits:
The Statement Sonata (the original from around 2009) - nice pickup with a beautiful warm, detailed and involving sound, but with a ridiculously low output of around 0.2mV (although Grado claim 0.5mV) so that even my ultraquiet Restek phono preamp with its maximum amplification of +66dB has a hard time getting to decent listening levels. The natural match was this:
The legendary Grado PH1 phono preamp, which runs on batteries - but while it manages to provide proper amplification, it is a bit noisy and adds some warm coloration which many find attractive. Yet it‘s sooo beautiful and sweet!
