The main poll shows the 510 to be the choice most people prefer, It used to show the 901. I bought my 901 when the poll showed it as the one most people liked and then after the 510 took over the list I bought one of them. I personally prefer the 901. I'd like to know which you guys prefer as the poll can let people who have only one or the other vote. please only respond to this post if you have both models.