Chadnliz
The RB 300 is a great arm. I see that you are using it with an Audio Technica cartridge on your Sota TT(how did you get it free, lucky you !!).The major difference between the RB 300 and RB 1000 ,IMHO, is a much greater retrieval of detail.As a poor analogy, assume the lp is a dirty carpet and the RB 1000 a more powerful vaccum cleaner. You are hearing much more of whats on the lp.To derive max satisfaction from a RB 1000 you would ideally need a cart thats best suited.I am not familiar with the Audio Technica and hence can't really comment on whether its a good match for the RB 1000 or not.As I discovered you can't really drop the RB 1000 into the same slot as the RB 300. The armband will need 3 holes to be drilled to accomodate the triangular mounting mechanism of the RB 1000. This is no big deal if you know a good machinist or have a good dealer. If you are in a position to go for it, I strongly recommend the RB 1000.Do however check out the other competing tonearms at this price point.
Cheers