This was the first all around great 3D mario. I'm surprised it took 2 gens to get all the rough edges sanded off, but maybe it was still extremely strong around the time for the prior 2. It feels like a good balance of sunshine and 64's best strengths, and even shows some portions of the DNA that became Odyssey, the still hands down best 3D Mario.

The added story wasn't anything to write home about, but it is nice you can either delve into it a bit or wholly ignore it(save for the opener). The spherical motion of the game doesn't break often, and though it can be frustrating when it does, not nearly as much as the frustrating parts of the prior 2 3D marios. and it's a blast to traverse. The motion controls were entirely unnecessary as the port proves, but there is some added fun in using them to some degree.

The level design which boils down to "what if space were collections of planetoids that feel like a mario level", but frankly this plays to the strength of what you find in sunshine. A lot of the design in sunshine is really good, except for the minor side stages, but this combines these together a lot more succinctly with few odd or overly frustrating choices. And it was really smart to use the comets to modify conditions on levels for some extra challenge you can totally avoid.
It's not -the- perfect 3D mario game, but it's definitely in the upper half of the ranked list.