I've owned both the LnL and the 650. Both are excellent. Here's my take: The LnL is ideal for loading smaller quantities of multiple calibers, whereas the 650 is ideal for cranking out larger quantities of the same caliber.
Once you get the Dillon set up and running, it's like a locomotive. Keep feeding it brass, bullets, primer, and powder, and it will just keep making rounds. But there have been many times when I felt like loading caliber X and the machine was set up for caliber Y, and I just wasn't in the mood to change it. (I do have separate toolheads for each caliber, each with its own powder drop. This helps a lot.)
On the other hand, it's far easier to get the Hornady set up for a particular caliber, but I very rarely was able to get it to run for 1000 rounds straight without some kind of little hiccup, be it priming or ejecting.
Dillon for quantity, Hornady for flexibility.