Original or Aftermarket Tach

[70StepsideC10]

I am starting to put together a tach cluster for my truck. I have found the tins for a good price, and the guy also has an original tach for sale. I asked if it worked and he said it can be tested when I am there to pick up the tins. He is asking $90 CAD for the OE tach. That might sound like a lot to the Americans on the board, but for comparison an aftermarket tach locally is $180, and if I was to order one from the US it would be around $150-$160 with shipping and exchange rate. Saving money is always good, but I would hate to buy the OE tach and have it fail. So I thought I would ask the guys out there that have tachs, either OE or aftermarket, what they thought. Do tachs go bad often, or are they fairly robust? Or should I spring for the aftermarket one and some piece of mind? Thanks in advance.