I've been using a Pro-ject RM10 with a Sumiko Blackbird cartridge since August of 2007. I find it to be very dynamic and musical. The Blackbird needed about 50 hours to break in (at first it was too clinical), but after that it's been one happy listening day after the other. The Scoutmaster was my other finalist, but I never got to hear it. I heard the Pro-ject 9.1 and bought the RM10 assuming it would be better and I wasn't disappointed.
I listen to classical orchestra, lots of brass, jazz big band, jazz vocalists, pop and cubano. The Pro-ject/Sumiko is involving and exciting to listen to. I've got a few duplicates on CD/DVD-A/SACD and vinyl. The vinyl ALWAYS wins the battle as more involving and richer. The timbre is the same and dynamics (at least on DVD and SACD) are comparable, but the RM10 digs out more details and more character.
About three-months in I bought the Speed Box II. It was clearly an improvement with piano recordings. I think it also added to bass dynamics, but I don't understand how. If you don't listen to a lot of piano you might do without it, but the convenience is nice. I was constantly touching the belt to move it and then worrying about cleaning it and the rim of the platter, so now it's clean and stays clean.
Dave