The old models are still great machines and I think the 2 big improvements are the x controller and the single x extrusion. I’m running a Stock old model and I love it, though I ordered the single x extrusion and will been upgrading it very soon. A lot of people here are running modified version of the old and with all their upgrades they might be far more rigid the the new stock model. Have a look around in the upgrade category. And so if you can get a good deal on the old model take it and put all the savings into some upgrades or just grow with your machine when you feel the need for an upgrade