Bones,
There will always be pros and cons about training in US vs UK. So people I know trained in US and got UK jobs. But then I would never get to know someone who trained in US and didnt get a job in either. The people I know who got UK jobs trained with HIA.
Important thing is attitude and professionalism. Getting training and ratings is a tick in a box - it allows you to apply for jobs in the first place. Getting the job is all about you and whether a chief pilot likes the look of you. In some ways, its not what you know, its who. If you want to fly in UK, there is a alot to be said for training here. There are loads of PPRuNers who will vouch for that.
I didnt go to the States because I didnt want to give up a good job while I was training / waiting to get a job. Advice I would always give is make sure you have a plan B. There are too many hoops to jump through / waiting to trip you up on the way to be a professional pilot.
Have fun and enjoy wherever you end up learning to fly. Learning to fly is one of the most exhilerating experiences and also one of the most depressing. All at the same time! And I would do it all again.