I previously put up a thread last June about a personal trainer.
http://www.askaboutmoney.com/showthread.php?t=84617&highlight=personal+trainer
That was last June, I knew I had to tackle things then, but went from bad to worse, had a bad run of personal problems. Eating (and drinking) habits went to pot. Result was I put on another 1.5 stone when I already needed to lose a stone. So 2.5 stone up. I am usually quite a motivated person, but was all over the place at that time.
Come January decided to tackle the weight, starting with exercise. I said I was going to give the personal trainer a go and I did. Sessions were €50 per session. (or block book 12 for €500) I did 2 sessions a week and although I did not lose much weight initially within those six weeks, I think I only lost about 3 lbs, but I really started to tone up. I stood on the fat machine (dont know if those yokes are correct and I had actually converted a fair few pounds of fat) Also it was only about 3-4 weeks into the exercise that I started to focus on diet. I did a lot of speed and reaction type exercises and also balancing. At the end of the six or seven weeks, I said I was going to have to go it alone, so bought a push bike - I go out most evenings, even if it is not far. Since January now, I have lost just over a stone and hope to lose another stone.
Went hillwalking recently and despite me never having done it before, was able to manage 10k (of uphill) and did not struggle at all and I reckon what I did with the personal trainer (balancing) etc really helped.
For me it worked, it was expensive and I thought long and hard before starting it, but changed my focus, so was worth it. Before people start saying, you have more money than sense, etc, I dont see it that way, it really helped me focus on what I needed to do. Not everyone is able to just motivate themselves to go out walking, running, etc and it does give you that push in the right direction. However, you have to be serious and about it and it is no quick fix. You will only get out of it what you put in.
Hope this helps