Yes its quite good but maybe all babies look quite similar in the womb as they are all bloated. But you can see the hands, feet, etc. quite clearly. If you go at the right time you maybe able to tell the sex of the baby quite clearly.
Quite a lot of OB have 4D ultrasounds nowadays. You should phone around and ask for the cost. In fact there have been quite a few threads on this before. Try searching this website.