Well, the skybox is a lot better - makes flying around ring systems much prettier.
In terms of major differences:
- if you're an explorer, it's a closer base than the bubble for about 75% of the galaxy, and stocks almost all the equipment you might need. You can also get first discoveries only 100 LY from home if you fancy a shorter trip.
- if you're a miner, all the system reserves are pristine
- if you're a trader, the economic balance is significantly different in Colonia (a focus on High-Tech, Service and Tourism economies) which may add some variety. Rares trade is not generally practical, though.
- there is no Powerplay or superpower-aligned minor factions
- mission generation is generally more stable nowadays than in the bubble (no extreme edge cases in either direction) and includes several nice ways to make decent money and/or G5 materials.
- with a relatively small number of systems, you can learn all of them and have more of a connection to them
- there are no Engineers (but there are remote workshops and material brokers are available)
- Community Goals are rare (approx every 2-3 months, rather than weekly) but always lead to some meaningful improvement for the region. Also there's a chance to get some extremely exclusive decals. Unlike Sol bubble, CG participant count does not significantly vary with CG type.
- Extremely high concentration of player-backed factions (and various other qualitative differences in the BGS due to how the systems were set up)
Whether those are good things or bad depends on what you like to do, but it's certainly very different to the Sol bubble despite the basic rules of the game being identical.
Edit:
Summary of quantitative differences:
https://cdb.sotl.org.uk/regions
Summary of qualitative differences:
https://cdb.sotl.org.uk/new