This seems to be one of those favourite points of discussion amongst student pilots.
I see your profile says you're from Canada, so I take it you're looking to train somewhere in Europe for a JAR-FCL?
Surely if you ask active pilots of any nationality they'll all tell you their licences got them a job. OTOH, the answers you will get here in an anglophone, mostly UK-centered forum full of students and wannabes (hence by definition, people who have not got the t-shirt), I doubt they will carry much authority.
But in any event, I'm not sure you are focusing on the right issue. Perhaps finding a place to train that you like, can afford, and feel satisfied with, is more important? At the end of the day, your competence as a pilot is exclusively down to you and the effort you put into it, the only difference being that making whatever choices are right for you may help you realise your potential. Remember those choices are not universal.
FWIW, I know that some continental pilots do their training in the UK as a way to improve their English skills. I suppose that is an advantage. However, not sure how much that'll help if English is your mother tongue in the first place...
In any case, from my personal experience, I would not say a UK-issued licence is generally considered any better than that of any other JAA country... except by the Brits themselves, of course, but that's the way they are.
I'm saying this anecdotically because I had problems hiring aircraft in the continent with my British PPL... people assume you've trained in one of the Florida schools and therefore can't fly. Best case, they're amused by the sheer volume of it (it's a DIN A-5 sized book), but that's all.
As for the CPL, if I were to do my commercial training again, I would not choose to do it under the CAA. Too expensive and too full of themselves. The only advantages being that there are exam sittings every month and they're reasonably quick with the paperwork (again, you pay for the privilege).
And to put things in perspective, remember that if you intend to make a career out of it (unlike some of us), getting the licences is not even half the battle. All it does is gives you the right to send a CV. So you might want to start thinking on a plan for after you become qualified--the licences, you just throw money into it and you eventually get them.
Anyway, it's all been said before, but the blurb above is to help substantiate my answer to your question:
all i want to know is will an air operator perfer one jaa licence's country of issue to another?
I do not know. I doubt anyone here can answer with any authority. It might not be a very relevant question to start with.
Hope this has helped. Best of luck whatever you do
