How do you choose a turntable ?

We probably never end up with the best turntable we can afford, but we can convince ourselves that we do.

OP, ..."ghdprentice, you approach it as a scientist or/and an engineer." 

Guilty as charged. I am trained as a scientist and worked as one for a decade and worked as an engineer for a while. So I approach things methodically. 

Depends on what level of turntable you are purchasing. Nuances/subtleties are magnified on a higher resolving system. Turntables all have a house sound. Clearaudio, Rega and VPI will all sound different with the same implemented components.

" Everything should be as simple as possible, but not simpler." Albert Einstein.

Turntable is a seemingly simple thing, it's not tape deck. That's the advantage of it. Well designed and made table can last for decades with minimal care. Might have to replace a motor. Decks can and do last for decades as well, not with minimal care, though.

I thought about it too. That turntables don't sound the same.

In a perfect world, when choosing a turntable I would compare its sound with Studer deck. The one that would come closest would win.