I've been really keen to try the new Supra for a long time now, so jumped at the chance to have a go last weekend despite the weathers best efforts, good grief it was wet!
First impressions of driving it are, the fixed roof does make the whole car feel that bit tighter than the G29, the dampers/springs are setup differently as well. Where the G29 had damper settings from Comfort through to Sport+, the Supra just has two. Normal and Sport. In truth, there didn't appear to be much difference in the two and both felt like the stiffer end of what the G29's dampers offered.
Over bumps the G29 does soak them up much better in Comfort than the Supra will however I suspect that's exactly what Toyota wanted.
Because it was so wet, I did get the chance to explore the chassis far more than the G29, grip is aplenty however give it a bootful on a tight corner and there's a lot of notice the rear end is moving. it's extremely easy to catch a small slide and the way in which it happens is enormously satisfying, I feel the fact you're sat further forward in the car compared to older Z4's helps here as it feels like the car rotates around you rather than something akin to being at the end of a pendulum. Again, I suspect this was Toyota's influence as it's an awful lot like the GT86 in that respect.
As with the G29, I wasn't so keen on how the seat wouldn't go very low, the interior is definitely a bit more upmarket feeling in the Z4 and that steering wheel on the Supra looks godawful. That said it's nice and slim so much nicer to use than the ridiculously fat wheel on the G29.
The styling is subjective of course but I really like the way the Supra looks with a fixed roof, far more so than the G29. I do feel like the front end has too many vertical lines that make it look tall and narrow. The headlights don't help this either, the size of them plays tricks with perspective because your brain isn't used to seeing lights that almost meet in the middle.
Contrast that to my E89 in the photo below and to me the Z4 looks the wider car even though it isn't.
Overall though I'd take this over a G29 any day, to me at least it looks better, drives better and feels more special. I reckon it might be a cheaper prospect than a G29 long term as well. BMW were happy to give a significant discount on a new Z4 whereas Toyota won't budge an inch. I think that for the first few years at least, Supra's are going to hold their value far better than Z4's meaning that although you might pay a bit more upfront, it'll come back around when its time to sell.
Alas the roof don't go down. 
