You are asking for answers but all you will get are opinions. I have found over the last 5 years that any printer that I have built that uses threaded rods for the framework did not hold resolution well. There is just too much give in the joints, be that from the plastic bits or the multiple joints. (Our first Kossel build also had to much "flex", turns out we printed with 35% fill but needed to reprint all the parts at 80% and now they are both rock solid. Also, if you do not get a printer with a heated build plate, you will be limiting your choices of filaments you can print with.