The low deck is roughly 7% shorter so as Dan said it's not really as significant as some think. However the rotating mass is that much ccloser to the crank and the low deck will have a lower center of gravity all else being equal.

any block is only as strong as it's thinnest bore.

Thew main advantage to the low deck ( to me) is they used to be cheap to find and the smaller journals on both the rods and mains (when you go 2.200) just helps the bottom end spin a little easier. and generally lighter is (if little more) extra insurance for when you over-rev. Headflow, cam and compression pretty much determine the sweet spot and the rev cieling, lighter bottom ends just get there a little easier and are 'less brutal' to themselves at thigh rpm.

Expert machining is the key to a great running motor, Typically experienced builders can tell how well a motor will run by the way it falls together, and also how well (or poorly) it ran by how it comes apart.