Go the Ultima, I bought mine based on StevenM's froth about his and am stoked with it.
I've got the same as him, the King - I'm 6'2" and have heaps of space inside, plenty of partner room too if you need it. I christened it up in the Snowies a few weeks ago, one night was tent-explodingly windy and I was fine except the gusts were coming straight head on, so it was getting up under the canvas over the top and was quite noisy. There are points on each corner where you can put pegs in which I didn't do, that would've solved it. Rain wasn't an issue, it was only light that night but I'd be confident in heavy rain too. Really roomy inside and totally dark once you pull the flap over.
Rolled up it's pretty big, especially once you put bedding in. This is it without a doona inside, so usually it'd be a little bigger than this (double bed & lazy dog for comparison):
There's a compact option too for an extra $10 or something, basically you fold the whole thing in half before you set it up and you can't keep the mattress or bedding inside so I steered clear.
I bought mine over the phone - called up late Friday arvo and it was at my door in Sydney on Tuesday morning. Make sure you get the pole kit.