I would say that it is probably an ok trade as long as the 125 appeals to you. I personally am partial to the NF tractors. I also don't have experience with a tractor like the 1210 so others' opinions are probably worth more than mine.
One thing I would check is the wear on the mule drive on the 125. I have one where the pulley hangers have bit into their mounting rod and thus they are angled a little but funny.
http://onlycubcadets.net/forum/showthread.php?t=17452 Of course it can be fixed but it is just another project.