Hi Peter, I went from a SME 20/2 IV.Vi arm to a Grand Prix Monaco with Triplanar VII uii arm.
First, I had my SME for years and really loved that table. There is a "rightness" to it's sound that I don't think can be bettered, except by a 30/2 or 30/12.
The Grand Prix/Tri combo over the SME 20/2 SME IV.Vi is better in the PRat, dynamics, more quiet, and images better. I don't know how much is the arm vs the table.
When it comes to a SME 30/2, you more likely getting different than a lot better.
I am very happy with my Grand Prix, If I hit the jackpot, I'd like to have a SME again as a 2nd table.