To my knowledge the Lock and Load Hornaday uses standard dies ( 7/8" X 14 dies ) just like the Dillon 550 and 650.
Dillon SDB uses a proprietary die - that is unique to just that press.
I agree its a big decision to upgrade ...and its not free...so you do need to look at all your options.
SDB is a good machine - it auto indexes, uses proprietary dies, is for handgun calibers only - will never have a case feeder or a powder check option. But I have friends that have used them for many years. Cons- no powder check, no case feeder.
650 ( more money ) ...but has the options for case feeder and powder check. Dillon 650 and Hornaday LNL are very similar in terms of capability. I think the Dillon is a better machine / and Dillons customer service is better - for advice, parts if you lose something,etc. But LNL is not a bad machine.
Most all of the big names ....Dillon, Hornaday, RCBS are making good equipment these days.....they do little things differently --- in how they handle primers and powder drops...they each have features that are not perfect ....but Dillon 650 has met all my needs ( I shoot about 25,000 rds a yr thru my handguns and load 9mm, .40S&W, .45 acp, .38 spl, .357 mag and .44 mag ) ...and for what its worth, I'd buy the Dillon 650 again.
We are considering a smaller house - 2nd home ..../ and if we buy it, I'll put another 650 over there with another gunsafe.
But good luck in your decision - no matter which way you go ---and remember to have fun with the process !