I like Vigouroux he has done a fantastic job for Swansea (and we would be screwed without him). When he first came I wasn't so sure (1st game I saw him in the flesh was against Cardiff at the Swansea.com) but he has won me over and is a good keeper at the Championship level.
Shot stopping is excellant, however his kicking leaves a bit to be desired and his command of the area also not the best, he is not the biggest, yes he's tall but quite thin and this I believe is why he does not command his area the best as he maybe lacks the strentgth to truly dominate his area.
For the aforementioned reasons I don't think we need to worry about losing the Vig and that he has found his level (i.e a good championship keeper)