I think SE is, for a pure space game, probably the best game out there.
Maintain ship's whilst you travel, have one large 'universe', no loading screens, seamless space to planet (use a re-entry mod makes it better).
If playing with a good ai mod, it is pretty difficult to travel in certain areas that are overseen by a faction.
Loads of mods that make the game fantastic.
I really like the look of SE, there could be more block types and textures (thinking EGS), but overall it's o.k.
However, if EGS had pistons, wheels, rotors etc, plus a single universe, then that would top SE.
But in other ways EGS does top SE. Building is much more intuitive in EGS, the choice of blocks is better and also textures for blocks. The colour tool in EGS is way beyond SE i.e. paint every side of a block a different colour or texture. Planets in EGS are simply amazing for me, way ahead of SE, although not seamless & much smaller (although they dont feel smaller) and done quite differently to your SE planets, but EGS gets away with it, because the planets are so rich in detail.
But then you come to no real moving parts in EGS. This makes SE the game for the builder imo, more options and more to think about tech wise.
I use the same ship in both games, well as near as I can get, there are those restrictions in both games. Building the ship in EGS was an easier experience, but the tech side is better in SE ie. piping fuel, air, using rotors, pistons etc.
Exterior/interior design wise, or for the look of a ship, EGS wins for me, it's simply down to the choice of blocks, colours & textures.
SE & EGS give players of block building games great entertainment in slightly different ways, but each can be enjoyed for that difference.
SE is top for me, but pretty close behind is EGS imho.
Note: walking around your ship whilst it travels along, doing maintenance etc, is also a massive SE plus, that EGS needs badly.
Both simply great space games, especially for the gameplay side.