It's definitely worth a look in its own right - while it started out as an Elite clone, it's developed further since - but it's also interesting if you never played the original Elite because it follows a few of the design decisions from that which weren't in FE2, FFE or Elite: Dangerous.
- jump range locked to 7LY for all ship types: this gives the map a very definite topology of routes. The recent versions of Oolite know whether or not a system is a bottleneck and spawn NPCs accordingly: try getting into the top-left of Galaxy 2 with a bunch of passengers or courier missions on board and you'll find out what I mean

- only enough fuel for a single max-range jump. Same fuel reserve powers your boost (once you've installed it). So if you make a 3 LY jump you can probably run away from most danger ... if you make a 6.5LY jump you'll have to stand and fight. Lots of places - see previous point - require long jumps to get into.
- cartoon scale (but Elite+'s non-player-centric simulation): this gives the ability for "living" NPC interactions to just happen, in a way that they don't much in the later ones. You can get attacked by pirates and a group of bounty hunters returning from raiding a nearby anarchy can see this happening and come to your aid. Or you can be the bounty hunter coming along and rescuing the trader from pirates. And then a Thargoid warship might show up and *everyone* will drop what they're doing to fight it regardless of their previous differences. Realistic scale is great for a lot of things (planetary landings, for example!) but I think it inevitably compartmentalises the gameplay.
And some innovations of its own
- jump time is proportional to the square of the jump distance, so lots of little jumps are quicker than one big one. This allows for some very interesting playing around with mission deadlines (and time loss as a consequence for your actions - whether needing to repair or being forced to do community service for your crimes) that means you don't always just pick "shortest route"
- it tracks your "profession" based on your actions, and uses this to adjust NPC behaviour. So if you behave like a bounty hunter most of the time, pirates will mostly avoid you unless they have you outgunned ... whereas if you behave like a trader they'll try to rob you ... and if you behave like a taxi they'll largely ignore you. Similarly if you get a rep as an assassin, the police may harass you even when you're clean - whereas if you're known to be a trader they might give you the benefit of the doubt when they stumble across you in a fight with another clean ship. Your reputation builds up quicker if you stay in the same place, whereas if you go somewhere new there's a good chance half the NPCs won't have heard of you.
- (EDIT) you can follow a ship through hyperspace just by flying into its wake, for no fuel cost. This was originally so that traders could have non-hyperspace fighters (Sidewinder, Mamba, etc.) as escorts ... but once it was in lots of other uses came up.
Plus all the expansions, of course.