The brown ones were better!

In terms of lifespan or the preheating of the electrodes?

I never saw the brown ones?, but I had loads of the green ones in service

Im yet to get a brown one but i have plenty of green ones with the brown pin inserts and tbh most of the ones i got are faulty lol. You flick the switch on and they wont do anything not even attempt to light the tube but if you switch them off and back on a few minuets later they will pre heat the tubes and light as normal and they do that all the time sometimes they work sometimes they wont do a thing????

Shaingout used the green one, inside the white cylinder of their Electronic-Start ballast: (...)

I've known a fair few of the green ones to suddenly just stop working. Usually they've not had much use either. Never had a brown one fail, they always seemed to last the life of the fitting.

Caps drying out? Some of these are probably getting on for 20-25 years old now?

I have had a brown cased one fail, it either wouldn't attempt to strike at all or would violently pulse the tube and cause the ballast to rumble, possibly damaged by an EOL tube left in for an extended time or as above dry caps, must have been in the fitting for 30 years though to be fair.
I've also had a couple of the green ones go, one was in one of those fittings with the starter directly under the tube cathode so it had been roasted for 10 years to be fair, but the other was rather poor and installed in my own Fitzgerald LP.40 for about 5 years so not at all hammered, but just randomly stopped working one day and never worked again.