I had a go with the sensation in a vodafone shop yesterday. I think it must have needed rebooting as it was terribly laggy, stuttered just swiping through homescreens. The screen is brilliant though. To be honest i couldnt see any difference except the standard lock screen with regards to how it looks, looks identical to my desire hd with regards to sense etc. My upgrade isn't until the end of the year so i'm hoping their will be more of an upgrade by then. Also the 1080p video recording was great, but i think that will very quickly eat memory space.
I also went into a Vodafone shop today to try one out and tried 2. One was like you describe, but worse. The other, straight out the box was excellent. I should have put my own SIM in though, as the one they stuck in didn't connect!
The problem with the duff one was that it was in a special security cradle which must have just been touching the screen slightly. So whatever you did with a finger just seemed to confuse it. Was the one you tried in a cradle?
However, I compared the signal level with my Desire HD and they were the same (both had a full signal). Back to the new one and playing about with screens and they spun around as fast as I could make them. Definitely as good as, or better, than my DHD. Screen was superb, looked brighter than mine but forgot to check the setting (mine was on max.).
What I like about it, apart from the fact that I like the latest and greatest etc ...., is the width and contoured edges make it a lot easier to hold than the DHD. The headphone socket and USB port are in more convenient locations, for me anyway, with regards to my car and desk holder setups. Also, it's supposed to have a HID Bluetooth profile so BT keyboards should be a lot easier to setup. (If anyone's tried this please let me know - separate thread somewhere).
Looking at the end of the month for an upgrade, but probably from CPW 'cos I don't want the VF SW crud on the phone..
Dave