Gilles:
I sort of agree with the others on this. In the US the H is a very common tractor and I guess to restore one would be more along the lines of having a really nice toy to play with, but would not be worth a lot as a collectors item.
However, that being said, I have not seen an awful lot of H's here in the maritimes, restored or not.. actually I really only know of maybe a 1/2 dozen. I am not sure how common they are in la belle province... so that would be a determining factor as well.
Either way, it would still be a fun project for one inclined to do so. My buddy Gord Trail has restored his H -- and it is a nice toy to go along side his Super A. I think the H was his father's though...
The only one who can really decide Gilles, is you.. think about it and if you want to get into a large, large project.......