Not very good if you are over 50, no matter how much experience you have. I have 20 years and 10,000hrs, mostly on heavies and not a glimmer of interest from anyone.
I'm giving it six more months to find a UK based job and then I'm packing it in. Most industries outside of the aviation bubble value a bit of experience in life. Not so with the airlines, all they want is wannabees young and dumb enough to accept handing over the mortgage on their parent's house, no-one else need apply.
I'm beginning to think they are welcome to it.