The solid wood makes a difference, but mainly for the top of the guitar. I have played many VERY good guitars with just a solid top, and laminate sides and back.

More expensive instruments are usually set up really well, and intonated perfectly for a certain string gauge (most often .12s). You will also hear that the tone is more balanced, and a lot of the extra noise you get from cheap guitars is gone.

If the guitar has a pickup system, more expensive guitars usually have a better one.

You don't need to go as high as $2000 though to find a close to perfect acoustic guitar. There are many very good guitars for around $1000 that are good enough for professionals.

A lot of the extra $$$ you pay above $1000-1500 can be for purely cosmetic improvements like inlays and the most beautiful pieces of wood.

I have played guitars that cost $5000 that didn't feel good at all.