Shimano has been making road bike derailleurs for a very long time now, so long that there is some confusion about the hierarchy of their vintage components. I’m going to try to cover all the old derailleurs I know of and give them a tier ranking of entry level, mid-level, or upper level. I’ll be referencing the current lineup a lot since most are familiar with it. Because of this I’m going to start out with their current lineup.
Current Hierarchy
Tourney – budget entry level. These are pretty good for entry level mountain and hybrid bikes, but I only see them on the cheapest of road bikes. I haven’t seen any of the good brands use these. Originally released in 1971 but has changed a lot.
Claris – this is the standard entry level road derailleur for Shimano, used by all the big brands. It currently has 8 speeds. It’s a little clunky, but reliable. Originally released in 2013.
Sora – I would call Sora lower mid-level. I think it’s really quite nice and feels much smoother than Claris and has 9 speeds. Introduced in 2012.
Tiagra – upper mid-level. A very nice 10 speed derailleur. Introduced in the late 1990s.
105 – this is the bottom of their pro(upper) level models. It’s 11 speed like the more expensive components, just a little heavier. I really like mine. Introduced in 1982.
Ultegra – the middle of the upper-level models. 11 speed and a little lighter than the 105. Introduced in 1988.
Dura-Ace – the top tier of Shimano road derailleurs. 11 speeds and super light. Introduced in 1973.

Classic and Vintage Derailleurs Tiers
300EX – lower mid-level like current Sora.
400 – these would be the Tiagra of their time, just below the 500.
400EX – upper mid-level like current Tiagra.
400FF – a 400 level derailleur for the short-lived Shimano front freewheel system. The freewheel was in the crank.

500 – in it’s time it would be like the 105 currently. It was similar to the 600, but heavier. Introduced in 1975.
500EX – lower upper-level, like current 105.
600 – these would later be rebadged as Ultegra. They were just below Dura Ace.

600 arabesque – a pretty version of 600. Design reminds me more of some Campagnolo components.
600 tri color – the last version of 600.
Altus – from best I can find out it was either upper entry or lower mid-level.
Altus LT – lower upper level like 105. Lighter and slightly better quality than the Altus ST.

Altus ST – upper mid-level like Tiagra. First derailleur with Shimano self-centering tech.
Crane – top of the line predecessor to Dura-Ace. Introduced in 1971.
Crane GS – long cage Crane derailleur.
Eagle – introduced around 1970. Entry-level derailleur, heavy and made with steel. Strong and reliable, has a bashguard.
Exage – lower upper-level, similar placement as current 105.
Lark – entry level, same as the Skylark, but with the cable mounted on a sprung cable saver arm.
Le Tour GT300 – these were made for Schwinn and are the same as the Crane GS.
Le Tour GT400 – Schwinn approved, the same as the 500.

Le Tour GT420 – Schwinn approved, never version of GT400, same as the 500.
Light Action – a mid-level derailleur like the current Tiagra.
Positron – Entry level, the first attempt at indexed shifting. Released in 1974.
RS – entry level derailleur that was an improved Skylark.
RSX – lower mid-level like the current Sora.
RX100 – mid-level, like Sora or Tiagra. Right below 105.
Sante – most consider upper level, between Ultegra and Dura-Ace.
Schwinn GT100 and GT120 – branded for Schwinn, same as Eagle.
SIS – entry level indexed shifters from the 80s.
Skylark – heavy steel, entry level derailleur. Same as the Eagle, but without guard. From the 1970s.
Thunderbird – heavy, early entry-level.
Titlist – these were just below the Crane, so the predecessor of the 600.

Titleist GS – long cage version of the Titleist, so the predecessor of 600.
And here I thought Sante’ was just a gussied-up 600. I don’t think that line stuck around long.
Yes it wasn’t around long. You might be right, info varies on that one. It’s at least 600 level.
I really have to thank you Jim, I love bicycling and I live in a very, very bicycle friendly city and you just about have convinced me I have to do it too. Greetings from València, Spain.