I am considering upgrading from my Prusa i2 to a new machine.

I am considering upgrading from my Prusa i2 to a new machine. However, I am torn between a Rostock type machine and a prusa i3 and was wondering which was better in the quality department.

I converted my Prusa Mendel to an i3 and couldn’t be happier. Minus the fact that the i3 is a cluster-fuck of non-maintainence. Have a spare printer handy.

Honestly with a properly built and configured i2, you can print as well as an i3. Though that is why I spent so much time rebuilding my i2 and redesigning nearly every part.
I can’t comment on a delta printer. But to me, the only upgrade would be to an overhead gantry like the ingentis or ultimaker.

Delta all the way just got mine built and can’t be happier with it. I also came from an i2 and it still works great, but the print quality on my delta is as good if not better than my buddies afina