Simply from an ethical perspective, it's not something that interests me. I think most of us are raising broilers to ensure they have been treated to a 'real life', where allowed to display natural chicken behavior such as scratching, dust baths and sun-bathing. So, it's not for me and I do not raise my pigs on concrete either.
The one advantage of using concrete which I see is that you can use your tractor/front loader to collect and spread the manure more easily.
On the other hand, if you just use a chicken tractor, you can put the broilers wehre you want them to place the manure saving you a step. I try and get my broilers over the areas I will plant potatoes and corn the following years.