Stock gauges Vs. After market gauges

Are the stock gauges really that bad? I always see pictures of people that have the stock gauges disconnected and use aftermarket ones.

Just today though I found a set of gauges for pretty cheap, so I guess I'll be doing the same thing. All I really needed was an oil pressure gauge. It just made me wonder how untrustworthy the stock gauges are? I guess they are 30+ years old???

It just seems to suck to have stock gauges sitting there that aren't going to be functional anymore. I guess it becomes a nice place for a tach??