To clarify, you are talking about the controller, not the monitor?
The SunSaver is likley a PWM unit, correct? What solar panel? Factory was likely a 12 volt, 100-160W panel. Just going to MPPT controller will not necessarily give you more power delivery. That is a major factor when you upgrade to 200W+ panels.
To get more info, you want less of the RV quality gear and get gear more aimed at the marine market, like the Victron stuff I use.
Now, all that said, if you do not yet have a shunt based controller (Victron Smart Shunt comes to mind) then get that before you upgrade your controller. It may give you all the info you need.
As for ease of plug and play, it depends on your skills or desire to learn those skills.
Please ask more questions.