Absolutely get the dillon 550 if you can afford it. However if you have a smaller budget, the Lee isn't as bad as you might think. And you'd likely never regret getting the lee and loading on it for a year then adding a progressive later. O actually have both the lee auto index turret and the dillon 550, in addition to two single stage presses, and I don't ever see myself getting rid of any of them. You could get into a complete lee setup for around $200, whereas a complete dillon setup would be closer to $750.
Oh, and to Shadowrider, I want to add the T7 to my group.
I am probably gonna start out with the Lee, mainly cause it is cheaper, and I don't wanna spend almost $1000 on a reloading set-up, since I've never done it and don't know if I will even enjoy it