I've picked up and moved a few times. For me, it's the only way to do it.
I'm not going to bore you with my experiences. Some worked out, some didn't. London was good, for a while.
A few thing to consider:
Have you budgeted in moving expenses?
Plane ticket, Are you going to ship stuff? If not, you'll need extra $ to buy neccessities. Anything with a plug, you're gonna need to buy there (except a mac). I blew up a few hairdriers, trying to use converters in London.
Are you going to be ok living a more modest life style than you might be used to?
When I moved to London, my first place was a B&B where I shared a room with 3 strangers and the shower was 3 flights down. My roommates were cool. We became good friends and ended up getting a flat together.
Public trans. is expensive, but there are so many great things to see in London, you might end up walking a lot. I did, even at night and felt safe.
I have to say Londoners and Britons in general are very friendly and helpful. Oh, and fun, too.
It was an amazing experience for me, kind of humbling. I'm so glad I did it. Having an open mind is key.