My experience with the 30 oz is not positive...the lid leaks slightly. I took the gasket off the lid and compared it to my Yeti gasket...definitely smaller. I'll post a picture later this week. The lid is slightly smaller, too. My other RTIC doesn't fit as tight as my Yeti, but it doesn't leak.
I'll likely just buy a couple Yeti lids and dump the RTIC lids.
I have removed the cup holder insert in my truck since the Yeti and RTIC both were tight. I'll end up putting a cut out of a mouse pad at the bottom to keep the cup from rattling on the hard plastic. I rarely use any cup other than the Yeti type anymore.