I looked at getting one of these around April time when they'd just come out.
Most of the shops reckoned that they were OK, but the touch screen wasn't very responsive. In the end i dismissed it and after considering a 'normal' Sony Ericsson and a HTC Desire, I went for the HTC.
I saw the other day that a bloke at work had a Vivaz, so I asked to have a fiddle with it & the touchscreen was absolutely awful; not so much 'touch', but 'press hard'.
The guy who owns it is well pleased with it, but I was definitely glad I didn't get one – would rather have had a non-touchscreen phone had the only option been this.