We did a shoot with Ambrosia recently (I'll hopefully be posting some large sample photos here later tonight), and it was much thicker than the Tesco version we usually use, and as Bill said, near double the price. The ladies tell me it tasted good though, and the cartons do look nice.
I tend to buy a full case of the Tesco ones at a time (IIRC thats 12 cartons). Runnier is better for clothes filling, especially if you want to get lots of it poured inside without making any mess on the outside to start with.