I looked into the G0750G when I was looking for a lathe years ago, not a lot of information on this model but looks very comparable to the PM machine. Looking at machine specification does not tell the whole story. I am not sure that the PM 1236 or G0750G would be a significant improvement over what you have unless your current lathe is worn out. Given the specs you outlined, I think the PM 1440GS would be a significant upgrade and you would have the larger spindle bore, otherwise you might consider the PM 1236GT. You can get a bit lost in the numbers/comparisions, I did that when I was buying my lathe and ended up with a 1340GT. At least for me, hands on experience was very different then what I read into the specs and features.
Just based on user feedback/warranty issues and length of warranty, I would think PM might be a better choice. My opinion is based on user responses and addressing warranty problems.