In reply to Ridge:
The photo here: https://live.staticflickr.com/65535/46938859615_5fd1290e71_b.jpg shows my first Yeti loaded up with "stuff" from my Dad's house that we were donating to a local charity shop. All three rear seats have been removed* but the spare wheel is still in place under the raised boot floor. Loading was a sporadic process over a few hours but it took myself and two hefty fellows at the charity shop warehouse a fair wee while to get it all unloaded!
Run_Ross_Run is correct that the 'secret' to loading the boot with the rear sets in place is to "think vertical" - it doesn't have a cavernous maw that you can just chuck stuff in to willy-nilly like the Octavia estate. But then it is 18" shorter than the Octy estate (although based on the same platform as the Mk2 Octy). That was a deciding factor when we were shopping for a new car in 2010: I was keen on the Octy Scout but the missus found it too big to drive with confidence, and was much more comfortable with the size - and the higher seating position - of the Yeti.
As rif says, it can carry a decent amount of stuff for a car of its size. I'm a little surprised at Durbs' account of not being able to get two suitcases in the boot. Again, think vertical, and use the flexibility to gain space if the boot if necessary - specifically in that case I suspect that sliding the rear seats forward might have helped, but you won't necessarily know about/how to do that in a rental car.
One of the things I absolutely love about my Yeti is its small turning circle - so often the difference between a swift u-turn and a significantly less swift and more obstructive three-point turn. It's one of the reasons why I bought another one when the first one was (a) getting on a bit and (b) at risk of being banned from LEZs due to only having a Euro 5 engine.
* Personally, I don't find the seats particularly heavy. They're definitely lighter than my towball fit bike carrier!