If you want a non-autoindexing progressive, then the 550 is your answer. As far as the Lee progressives go, if you were frustrated by the SDB, you will lose your mind over the lee. All Lee progressives require endless tinkering and readjustment to run correctly. Yeah, I know there will be somebody jumping on to talk about how it's the greatest kit in the world...but there are people who think Trabants and Yugos are great cars if you just learn a few little tips and tricks. Buy once, cry once. Get the 550 and take advantage of the massive used market for parts, conversion kits and the support. I have a 550 that started life as a 450 in the 80s, I've loaded literally millions and millions of rounds on it, everything from 32 acp to 338 Lapua Magnum. In all that time, it was upgraded once from the 450 to 550 because I wanted the toolheads instead of fixed...and once I sent it back to Dillon for a complete refurbishment which cost me 89.00 and I got basically a brand new press back. In my entire life I've seen exactly one Lee progressive press run flawlessly through a single run of 2,000 rounds. And that was owned by a good friend of mine, a machinist by trade, who was originally given the press because it didn't work and over the years he had replaced about 20% of the press with things he made himself. If you like to tinker, get the Lee...if you just want to unbox it and run it...get the Dillon.