I think the Pak 68/3 board and the SST are pretty comparable. Both offer 68030 acceleration, fast RAM, FPU support, etc.
The Pak is a bit smaller, footprint wise, and does offer up to 64 megs of fast RAM support, IIRC. To be fair, it requires
a second daughter board to do this.
The Pak also has a fall back compatibility mode. I don't know if the SST has a mode like that or not? Maybe Darren can tell
When I was subscribed to Current Notes (a US Atari magazine), Dave Small was one of the regular writers and I avidly looked
forward each month to anything he wrote. Great guy, the Atari community was lucky to have him with us.