I bought an early eighties 28M thompson this year and have pumped around 2K yards without a hitch.  I had one hyd. line break, but a quick onsite fix. Boom was inspected and in good order. I have around 400+ foundations to pour this coming year and I doubt I'll attempt an upgrade to a newer pump.  All the pumps wear parts have been replaced and I can only imagine what she pumped like in her prime, cause she'll chug along with 150 yrd pours without skipping a beat.  I think it says alot about the quality of thompsons. Putzmeister must have also thought so, or they wouldn't have bought them out.