I did get a couple of F3 back-seat trips with a mate down on 1435 and I think the most impressive bit was the acceleration from around 450kts+. The non-turning, more burning and slippy version was exceedingly quick at low level. Even easier to breach the exact same speed limits we had on the GR1, if you remembered to toggle the HUD speed display....
The first abridged trip was enlightening both for the much-improved view from the boot and the confidence displayed slamming into full burner at low-speed and high-ish AoA - something we treated with more caution on the GR1... only to be treated to a lot of banging and thumps through the aircraft with the stagnation of one and the loss of the other (both recovered ok but one of them had to be changed afterwards). Somethings were different, others just the same!