Simpsons Chubby 1 in Super at their list price is £124 inc. VAT. For a 23mm knot with a loft of 46mm, handle height 41mm.
The "Best" model is £85.
A Duke 3 in Best is £76. For a 23mm knot, with a loft of 47mm and a handle height of 46mm.
Of those three, the Duke is by far the best value if you want a Simpsons brush with the same knot size as a Chubby 1. The "Best" grade and density make for a very good all round performance.