the SME 3009 S3 could be rigged with supplied counter weights to have a higher mass making it more suitable for medium compliance cartridges. The series 3 was highly regarded in it's time (slightly later than the BW) however it just preceeded the arrival of 'super' arms like the Breuer and Sumiko's "The Arm" and SME soon developed the Series V
+1. Like many things in its era, the timing was wrong. It's actually a very good arm. Try to use a low compliance cart on it is asking for trouble though. The drawbacks are few, but can be show-stoppers: the arm wands are almost impossible to re-wire, and if you don't get a complete set (with all of the tools, weights etc) it's going to be trouble. Unfortunately, even the bias weight and arm is different from that on a series 2. Because production was stopped earlier than the others, spare parts are hard to find and can cost a lot. The arm wands fetch over $100 alone on EBay.
I too am a fan of the 3009 s3. Mine came with all the accessories and an extra arm. I run it with an old Shure M44.7, and the sound is big, lively, fun. I used it for a while (on a Planar 3) with a Mac MA6100 and the Ditton 25s I picked up from you (old_school) before you left these parts, and it sounded fabulous. I'm working on the Rega, which developed speed fluctuation problems, but I'm looking forward to getting it back in the rotation (ptp).
Nice to hear you're still enjoying the 25s Ben. I also have a S3 with all the kit and an extra wand. I have a V15 III with a JICO SAS to use on it, but the whole package has been sidelined for a bit until I get a new plinth built for either my Lenco or the recently acquired Garrard 401. I'm hoping to install it as a second arm.