I read lots of posts and try out many of the keyboards personally. For that price range:

Yamaha PSR3000 without a doubt is the best in this price range. Best sounds, styles, mic harmonizer that can make you sing like a choir. The most logical keyboard layout that won't make you frustrated.

You can also get used keyboards like PSR2100 for a lot less money but not as good as above.

My best advise is to buy it at Guitar Center or any retailer near you where they have 30 days moneyback. You cannot afford to spend that kind of money without assurance that you can return it at no risk. By the 2nd week, you will know whether this keyboard is for you or not !