I was immediately struck jumping from one to the other how different they are in character.
I think the 1.2 FIRE is great, pulls surprisingly well for a small engine. The 1.0 Firefly feels a bit gutless by comparison, it lacks the low down torque that makes the FIRE feel so flexible.
After a week I felt I was still trying to understand the 1.0 Firefly, using bootfulls of revs pulling away to avoid bogging down, having to keep the revs up going uphill, even having to drop a gear on motorway inclines where the old 1.2 wouldn't need to.
Also found the variable amounts of engine braking hard to predict on downhills as the BSG regeneration cuts in and out. The effect is quite strong, then you find yourself accelerating again.
But I didn't really mind it, I'm used to small engines and having to work them hard

The 1.0 Firefly copes absolutely fine on the open road.
I think I've just been spoiled by the surprisingly good 1.2, it pulls better than some 1.4s I've driven, and it would be my preference for out of town driving.