Functionally I do not think you would see much difference, they are made by the same factory and the original manual showed both. I had the 1340GT, very nice lathe, you will not be limited by the machine and these will hold close tolerance work. Weight is an advantage, but the 1236T is just a slightly shrunken version of the 1340GT so should not be any rigidity difference or differences in ability. Slightly smaller Hp motor and 3 year warranty on the 1236T instead of 5 year. I do not expect you would have any long term problems with either, I sold my 1340GT after having it for 7 years and probably it was just getting broken in when I sold it, never had any problems with it. If anything some of the feed controls were a bit stiff until they are worn in. I currently have an ERL-1340, but much more expensive and headstock is about 4" wider than the 1340GT. If your planning on doing mostly small work, you can't go wrong with either the 1236T or 1340GT, not much else out there that is the same quality at the price level. I liked the 1340GT just because it was a bit bigger than a 1236, foot print wise they will be about the same. The 1K price difference can get you a QCTP, DRO and maybe a better chuck. Really depends on how tight of budget you are working off of. Chucks have been discussed quite a bit, if you plan on using a 3J scroll, consider upgrading to the Chandox Taiwanese Set-Tru type, otherwise their 4J independent is very good quality at the price point.
I went with the 3 phase version with a VFD, I feel you get better surface finish and less long term motor problems seen with single phase motors. Starting out with the 2 Hp motor is probably a better option with a VFD, gives you more usable torque and Hp. You also get fast braking with a VFD, which was one of my concerns with not having a mechanical foot brake.
