I have heard others who have had trouble with the sex-links. They are prone to internal laying, but we haven't had any trouble with that so far (fingers crossed). We tame ours with treats and handling while they are chicks so they aren't so hard to catch and are a lot calmer. We find that our hatched chicks are a lot quieter and calmer than those we had shipped in, too.
Good luck with your ISAs! You'll be having fresh eggs for breakfast soon!