MPPT milks every possible watt out of a panel. Running large arrays it makes sense a 20% gain is like adding a couple extra panels. Small systems it is usually just more cost effective just to get a panel that is 20% larger and run a cheaper PWM controller. The exception is if you are package limited to a smaller panel, in which case you can't just fudge it with a little larger panel. Using good stuff, a MPPT controller is much more expensive than a PWM. 2-3x more. Of course there are cheap products out there. Some even know to claim MPPT even though they are only PWM because they can get more money. Offshore marketing is a bunch of liars most of the time.
I run a little sunkeeper SK6 on my panel. They are one of the few that will publish the dark power, how much does the controller take from the battery at night when there is no sun. Most won't publish this, and if they do it is often quite a bit. If you have a huge battery bank that is no big deal. But running a single battery it can matter. You could find yourself in the morning with a low battery that was run down by the charge controller that should have been keeping it charged. The sunkeeper is less than 2mA and some that did publish numbers were over 100mA nighttime consumption.
As far as the comment that I need 200W of panel to run the fridge, you must have missed that my 70W panel has been doing great for about 6 years now. And the fridge gets a workout, I live in AZ. I can't keep stuff frozen overnight, but cold it will. That is why I said I run a fridge and not a freezer. Well I have left it on freeze overnight, once, and it stayed frozen, but a single battery isn't enough to run that. So it is a pointless exercise in battery abuse. And sunshine came to the rescue in the morning.
For a single battery system, 50~75W should be plenty. If you are not pulling juice during the day all that goes into a charge.
