I don't know too much about this variable speed lathe, but years ago Rockler jumped on the 10 x 18 Mini Lathe bandwagon with "their" Excelsor MC1018 lathe. Basically a re-branded Grizzly H8259, Rikon 70-105, and Harbor Freight 65345. All with the same castings and layouts but different colors and badges. I started out with the Harbor Freight until I upgraded to the JET 1224VS.
I'm not sure about this newer Rockler Midi. So far I haven't run across other brands that have exactly the same spec's, but going from just the spec's it seems like a beefy enough Midi with a 1.2HP motor. It looks solidly built (judging just from the photos). To me it looks a lot like just an upsized version of their Mini lathe - based on how the motor mounting system and some of the other accessories look. I agree with Hank (leehljp ), Rockler branded tools are usually good quality and Rockler has built a good reputation so I don't think they would jeopardize it by selling substandard stuff.
Like David (d_bondi), my JET belt position has never been changed from the 220-3600 range as it covers all of my penmaking needs, even on the low end as I apply finish somewhere between 300 and 500 RPM.
Regards,
Dave