I use steam and sometimes spray sizing (never starch). I do use an expensive Rowenta because it is the heaviest iron I've ever used and I like the stainless steel bottom. I like it heavy so that I don't have to push down hard. My daughter (who is not a quilter) couldn't understand why I would pay so much for an iron --- until she tried it and then she bought one for herself as she said it's the only iron she's ever seen that levitates when you press "steam".
The most important thing is to never, ever "iron".
Always "press" and you'll never have distortion or stretching.