I am biased about the product but I am a huge fan. All of my new purchases are almost exclusively Sunset / 3rd Rail / GGD. I've got around 50 passenger cars, 4 brass steam locomotives, and over 30 diesels. Great looking but also great running. They always show well on the club layout.
Looking forward to the F3s arriving in about a month and very excited that Amfleet / Viewliner cars are FINALLY going into formal design as are the GP7/9s.