We looked at the Fiamma Caravanstore and the Thule, and went for Thule in the end, mainly based on how well made and easy to use we find their bike racks and other accessories. We also bought the Thule Quickfit Awning which attaches under it to make a more conventional awning with sides.
We are incredibly happy with it
It takes us less than 5 minutes to open out the canopy, and then another 15 or so to attach the awning if we bother to use it (awning only takes so long because we've only done it a couple of times, mainly because in moderate weather you simply don't need it).
It was a right faff to attach it to the caravan's awning rail, mainly, as we realised after a while, because there was a little nick in the rail which was impeding it sliding on well. And we decided to do it one windy, rainy afternoon in a rush. Hindsight is a wonderful thing. But, and the big but, once it's on, it's on. We've used it in the UK and France. It doesn't get unbearably hot underneath. When we had 'the wettest ever summer holiday in France' this year, we eventually put up the awning as a few things were getting wet, but for a weekend away we simply don't bother taking it.
We were away with friends who have the Fiamma version on the same caravan as us; ours seemed a little sturdier and I think the canopy rolls out slightly further too. Just remember to only buy it as long as the straight length of your awning rail!