Dillon's warranty cannot be matched. Easy set-up allows me to switch calibers in about 30 seconds. I have 3 different reloading blocks set up that I only have to make minor adjustments to in between loading for that caliber. I got my Dillon off of GunBroker. Picked up their maintenance kit and it runs like new.
I've heard good things about Lee loaders, I just haven't ever used one.
It depends what your goals are. I am not a high-volume loader, so the Lee turret press is all I need. If I were going to turn out 10K+ rounds a year, I’d need a Dillon progressive setup.