Now, I’m able to answer my own question since I got a -very- good offer on the MFR-1110, so I bought it
The answer is, in my case, although I notice the difference in the heat-up and soldering duration in favor of the MFR due to the higher power, I would not consider it worth the upgrade if I had to pay the regular price!
Other things are, I like the slimmer SXP cartridge of the MFR compared to the SSC of the SP-200. Also, the MFR is quite; no transformer buzzing!
All in all, I like my new MFR very much