I still love my 20oz Rambler tumber and 10oz Rambler low ball, but with all the hype about the other brands, I've been trying to find some of the cheap "knock-offs" in stock, but I haven't been able to until today.
My local store stopped carrying Yeti and started carrying Orcas instead. I've also been seeing RTIC and some other brand talked about lately and, even more recently, the cheapo Walmart Ozark Trail tumblers. The OT ones have been out of stock at Walmart for a few weeks now, so I signed up for email alerts and they came in this AM.
They didn't have any 20oz models there so I can't do a side by side comparison between the brands, but there are plenty of side by side youtube videos and reviews online that show other brands doing as well (or better) than the Yeti ones. OT is around $8 for the 20oz and $10 for the 30oz, and I've been wanting a bigger one anyway. I'll post with how it works but so far so good.
[youtube]http://www.youtube.com/watch?v=p5-abqaKWAw[/youtube]
eta: There are also a lot of rumors floating around that the Yeti and OT tumblers come from the same factory. Not sure if true, but they are VERY similar in construction. Like... identical except for the brand stamped on the base and molded into the lid. Also, lifetime warranty on OT vs 5years on Yeti. I believe Orca and others also beat Yeti on the warranty.