It depends upon what your needs are. With the advances in materials and manufacturing processes, the lesser expensive bows of today are already vastly superior to even the top of the line bows of even 5 or six years ago. But even still, "vastly superior" is a VERY relative term. but then again, so is the term "need."

All you need to do is to have a bow that you can fire an arrow from with relative accuracy.

That said, some of the qualities from a "top of the line" bow include:

1. Vibration free
2. Hand shock free
3. Noise free
4. Build quality / materials
5. Smoothness of draw
6. Speed

Generally, the more you spend, the more of the above you get.

If these things are not important to you, then no, you will get nothing more from a more expensive bow.