Went for the plunge on 'Straight fit Chinos from Next (UK)' in a 30 waist, short length (which I'd get hemmed).
I've had slim fit in the past.
I'm really liking the Straight fit actually:
-Nice silhouette/ breathing room.
-Not to baggy (disclaimer, Next bottoms are somewhat inconsistent in sizing/fit...).
Only worry with the the Straight fit is the 'bagginess'/excess material in the ankle/opening area/near the hem (as depicted in comparison pics).
But it looks like the Slim fit hugs the back thigh/legs/bum area more (stretch/creased material), so Straight looks like a better fit overall.
Do winder fitting chinos/pants need wider/bigger trainers? I'm sure I read that somewhere...