Over the years I've tried almost every thing. If you don't mind the l plastic look of the films, my vote would be for Ultracote. Why? Because is't a softer more rubberier material that stretches around compound curve much easier than Monocrap:-) I like the fact if uses less heat 250f, almost no such thing as a wrinkle you can't get out with ultracote. If you need to remove it a few years down the road, heat it and it comes of in one piece unlike monocrap that is more like string cheese.
If you don't mind the weight, 21 century fabric looks real nice, more like paint. But I've had many bad rolls of it over the years. Color that come off on you cleaning rag, rolls with out adhesive on the back, rolls with the backing on the front side thats hard to remove. Whites and Dark reds have given me these probs.
I know there are many out there that like monokote so less here what you have to say. Blotchy sun spots, haziness and stretch lines?