I just rewatched that after having seen it when it first came out, and I think it's harsh, and more reflective of his personal preferences than of the bass itself. There are owners in the comments that love it.
As for his criticisms of there being a 3 way pre onboard and it being too much for a beginner, what a load of bollocks, especially as he then goes to praise the Sire which is similar. Just centre them, set the volume and play. This comment makes about as much sense as saying someone learning to drive should only have a 90s car as the new ones have too many things to distract the learner - note, I had an instructors licence for many years.
Also his criticisms of the small neck and body, which is a preference for many like me, are obviously not just for him A P, J or Stringray feel like massive slabs to me and are less comfortable to play for that reason. I have no issue with the tone I get out of my SR375 with Dunlop SS rounds on it, though I might change these to the similar flats when it needs a new set of strings for another tonal variation.
I like Lobster's reviews in general, but don't take his opinion as gospel, just another datapoint amongst many. @BigBoar, please go try one and see what you think first. If there isn't one available locally, the SR necks and bodies are very consistent in shape and feel so a similar model in a higher or lower model will give you a good idea what it will feel like in your hands ergonomically, so if you like say a 600, then a 300 will feel very similar.
Note, I'm a bit of a Soundgear fanboy as I have a 4, 2 5s and 4 6s, so likewise take what I say with a grain of salt. My hope is that you like like the 300, but if a Fender or other brand works better for you, that you get that and simply enjoy playing bass.
PS: as you're a beginner, don't worry AT ALL about tone as your palette will develop over time and change with the years as you get exposed to more basses and how they're used in various genres and mixes. Right now, you need to focus on technique and learning how to play. Avoid tonal cork sniffing at all costs as it's a distracting path to hell.