Vantaggi
As a contractor, their only responsibility with you is to pay you on time and send you the renewal of your contract every year which I guess they do (the renewal).
Svantaggi
If for some reason they are still on the market as an employer you will get your payments on time every now and then, You may get paid anywhere from: on time, one or two days late or as I recently experienced, no pay at all. Several peers have gone through the same scenario as me, so I guess is a generalized way of operation, no serious company will do this and fail to communicate to their employees, they are not transparent which says a lot about their Management.
If you have more options, just skip them.
You never get any kind of communication from them, the only way you will get an email is because you have a renewal coming or your contract is not renewed, that is it.