I had one back in the 70s on an SME 3009 arm and a Thorens TD-124 table along with the Ortofon step up transformers. It was an excellent, excellent performer into a McIntosh MX-110 tuner/preamp. The whole set up was stolen, however, and I've never gotten over that in some ways.
Today, however, any original SPU cart will likely have aging problems with the suspension system which would require a rebuilding to make right. As for the value/$$, that's going to be a good one today. Frankly, I've pretty much settled for an Shure M97 of the latest vintage and have found that the Laws of Diminishing Returns catches up with you quickly after that.
Yes, they were heavy trackers, which flew in the face at the time of lighter and lighter tracking. This was a selling differentiator for Shure and most all cartridge manufacturers followed along. Ortofon SPUs and Denon's DL-103s were the exceptions. Again, I found that the SPU tracked just fine at around 2 gms and I never worried about LP damage.
Remember, though, that I am posting with 40 year old memories so take it for what its worth.
Cheers,
David