I'm pretty far into my training and in a specialty I like, and it can be rewarding at times, but it is a lot of hard work and I have found the rewarding aspects of the job have gotten less the more senior I have gotten (not sure if I'm just desensitised to them now or if it's because I spend less time meaningfully with patients than I did when I was a junior and that's the bit of the job I find most rewarding).
I think I would do it again if I was 17 back in the year I applied, but I don't know that I would do it now. When I applied, the tuition fees were a fraction of what they are now and you had a guaranteed job at the end of medical school with a good salary and clear career progression so you were rewarded for your hard work. That just isn't the case any more - you come out of medical school with insane amounts of debt, and we are now at a stage where medical students are no longer guaranteed a place in the foundation programme, and if the do get through the foundation programme, they are competing on equal footing with people everywhere else in the world for specialty training numbers because local graduates do not get priority. The pay goes far less than it did 15-20 years ago. You no longer get hospital accommodation in most parts of the UK so not only are you working 12-13 hour shifts, but you are spending additional hours trying to get to your shifts (my commute for most of my training has been 1-1.5 hours each way; was up at 2 hours each way for a period during the train strikes). Yes, the rota patterns are better than they were even when I graduated 9 years ago but the work is harder, the better shift patterns come with less continuity of care which creates multiple additional issues, and you feel less part of a team because you never work with the same people.
I'm not saying I've had bad time of it myself, I've mostly enjoyed my time as a doctor, but this career is no longer the deal it was when I was applying to medical school and future generations of doctors are going to have a much harder time of things.