squeek,ive had a 550 for two weeks now.
the main problem is that it makes me want more,and to get more you have to pay a LOT more.
the sounds are great,it is very simple to use,even for a beginner like me.
if you can live with only 2 variations,1 intro,1ending-----and only a headphone jack for an output,then you will LOVE this keyboard. I am still considering trading up,but still not sure to what. I may just have to wait for the new 1000/2000 models in the fall.but for the $500 price range-this baby rocks!
Bill