I have often wondered the same thing... but I'm willing to bet you will get every single type of response on this forum with nothing concrete to further your curiosity.
My TT is of the heavier version and I do attribute that to a better build. It's not to say I didn't have some initial issues with it, but all of those got fixed. Heavier TT also would lend to more features, slides, etc. Also, keep in mind that for all "appliances", those can generally be the same across the board for more expensive, cheap, light or heavier TT. So failing appliances would be mostly independent of the build quality.
