Personally, I need/enjoy the group fitness atmosphere because it motivates me more than I can myself. The coaches are very motivating and encouraging too. The scheduled class times offer a wide variety to accommodate anyone... What's not to like :) Getting in shape has never been more fun for this fifty-something year old!
I love the coach motivation. They know each person and ensure that they are doing their best, whether it's form, weight increase or pushing you to your maximum capability. An all around great 1 hour workout of cardio and weights!