Honestly, you can ask as many people as you like, dig as deep as you like - you will never ever find a negative story about Matt Smith. You simply will not. Everybody adores him.
He makes the crew work faster. Marcus Wilson [the producer] would always get him to the set quicker than he needed to, just ‘cos Matt’s presence gets everybody energised. He is tireless - not just in his performances, but with the extra demands of being a leading man, of being the company leader. He is so good at that and yet he works so hard at his own performance.
I will miss my friend [and] I will miss the most tireless and inventive actor I have ever worked with.
Steven Moffat, paying tribute to Matt Smith. Doctor Who Celebration, London, 24th November 2013. (Panel transcript via DigitalSpy