"Everything I read claims the 10 is another step up in improvements. Are you meaning the 8 has a better value/looking for overall best sound. "
I would stick with those claims. You're always going to encounter opinion with "better value/price ratio" with everything audio.
Based on your budget for the Mac table, if do keep the Rega P10 as your final choice, get the Apelian cart to go with it. You are going to plug it into a proper phono stage-$3-5K?
The MT5 is made by Clearaudio-there are options in your budget likely equal to or "better" than the Mac facade.