I would suggest that when buying a machine....think about what you want to do with it. Then, from there, start pricing them.
I think the $$$$$$ ones can and will do the same job as a $$ machine. You really don't need all the bells and whistles to make anything great.
I'll admit, I have over 100 stitches that my machine will do, but I have yet to use them all.
You get what you can afford and what you feel comfortable with. I know a lady who went and bought a cheap $100 machine from Walmart and puts out some AWESOME things with that.
Just my 2 cents!