Basically from what i've heard, is dentists get much more pay than doctors in UK especially if you have a good practice. If you specialise and go into Orthodontist then even more money can be made.

But also in medicine in UK the pay is increasing, especially if you are a GP.

The first 2 years of the course are similar, since you learn roughly the same stuff, but then in the clinical years you get more practice dealing with patients in dentistry.

At the end of the day it's up to the person himself, whatever field they are interested in they should go for.

Me personally, I would prefer medicine due to the depth of the course, and the variety, you can choose to specialise in anything that suits you, e.g. become a GP, become a surgeon, become a pathologist...etc