Guy,
I use both a Hornady Lock and Load Projector and an upgraded Dillon 450 (the press that evolved into the Dillon 550B).
The Projector does have a fifth stage. Unlike the Dillon press, however, the Hornady doesn't expand the case mouth and dump powder at the same station. An expander die goes into station #2 and the powder measure goes into station #3.
Dillon
1) Deprime, resize, and prime
2) Expand case mouth and dump powder
3) Seat bullet
4) Crimp
Hornady
1) Deprime, resize and prime
2) Expand case mouth
3) Dump powder
4) Seat bullet
5) Crimp
The only way that either press could use a powder check die would be to combine seating and crimping in the last station and replace the seating die with a check die, or to replace the Hornady's expander die with a combination expander/powder measure (like Lee's) and replace the powder measure with a check die.
The Hornady has auto-indexing and the Dillon doesn't. I don't find that this makes much practical difference.
One area where Dillon has Hornady beat is the priming system. Dillon's works smoothly and reloads quickly; Hornady's needs some tweaking to work right and requires taking off the whole primer feed tube to reload it.
Dillon's roller handle is very nice but it costs an extra $25 or so.
Hornady's Lock and Load quick-change die bushings work reasonably well. I don't know if they're a great deal faster than ordinary dies with good lock rings. The Hornady does make removing and replacing the powder measure quick and easy, which is helpful if you like to switch powders frequently.
