Fightin words, best transmission, 150/1500 series?

You can't go wrong with any of them. Transmission issues are getting to be a pretty rare occurrence on well maintained vehicles in general. Sure you have failures every now and then, but there aren't many vehicles out there that are still prone to failure. Transmissions these days do a really good job of protecting themselves. GM, RAM, Ford, Nissan, and Toyota are perfectly fine to go the distance. It's really down to personal preference. Some prefer the feel of the the old 5 speeds while some can't wait until 12 speeds come out. Some refuse to give up their stick while some refuse to go back to them. Some like trucks that shift at certain points while others prefer other shift points.