Yes, there are continual revisions / updates, but no, I don’t think that these should put anyone off from buying an older unit.
The changes I think would apply here are:
- low profile enclosure: https://docs.carbide3d.com/assembly/low-profile-housing/ — not sure about the specifics of this, I’ve never seen one — I think it would be slightly easier to install, and the lower profile is a nice improvement
- steel core belts — these are a recent change — I’m still using fiberglass on my XL, but upgraded to the steel belts on my SO3. Pluses are easier to install and tension, possible downside is lessened longevity, jury’s still out — you could get up to them by getting the Maintenance Kit (which I’d recommend for anyone, it saves a ton in aggravation and gas and not waiting)