Uncle Bill, I'm a Spotmatic anti-fan. This for two reasons.
When I went shopping for my first SLR, I found stop-down metering an, um, impediment to progress. I fully appreciate that it can be lived with.
I spent 1970 in the US Army in Germany. Most of my fellow soldiers took their snapshots with Spotmatics, which were then the least expensive nice camera in the PX. I don't know whether it was due to the users or the cameras, but enough of the Spotmatics I was acquainted with to notice had shutter failures.
I didn't get a Spotmatic, instead bought a Nikkormat at the 4 Wing RCAF's spring photo fair, still think its the better choice. Heavier, though. Having the shutter speed control concentric with the lens mount still seems more natural than putting it on the top plate.
And your brother's right, there's a lot of very good used glass around for M42x1 SLRs that's now quite inexpensive.