Azada, mattock or spade? Which is best? Pros vs cons..?

I would add, 'let the tool do the job' and choose the right sized tool for the job. They cut under their own weight and don't need swinging/as much force as you think at first. I really hurt my hand from the shocks coming up the handle from using it like an axe in my early days, gave myself a 'trigger finger' that needed treating too. Even broke a handle! (Always have an interesting conversation at the airport!)

I've known Portuguese farmers who have been using them for over 60 years who have never broken a handle, so it's worthwhile learning how to use one properly. 

SS