MPPT vs PWM charge controller in an always cloudy scenario

[Mike90250]

MPPT cannot create power out of thin air. It can "tune" the harvest to the maximmum that the panels can produce. But a cloudy day, you cannot expect more than 10% of nameplate from the panels.

[Alex9]

I read the Sticky: Off-grid solar charge controllers by Jonathan Cole. He says ho pwm for smaller systems and others say go mppt for 200-300w+. I also read that mppt gives you a distinct power advantage especially on cloudy days.
I live in a part of Hawaii that can be cloudy for >70% of the year. I'm looking to install a 12v system around 500w and we'll adjust our 24hr usage to however much power we can get on a given day. So, hypothetically, if everyday is a cloudy day, will having a good mppt cc like the TriStar TS-MPPT-45 be worth the $400 for me? Will it give me that edge vs pwm?
Any input would be appreciated.