I have OEM20 wraparound and I think its only drawback pag direct sunlight is kita pa rin yung loob. Di ka easily identifiable, but maaaninag ka. If you want complete anonymity in the morning, OEM5 is better. But I've had OEM5 before and ang layo ng visibility sa OEM20, much less sa VK70.
When parking in indoor spaces with the OEM20, I don't usually have to roll my windows down, though of course doing so increases visibility significantly.
Heat rejection is okay, better than my VK70 actually under direct sunlight. Sa VK mararamdaman mo pa yung init, sa OEM20 hindi na masyado. This is despite the VK70 having 55% TSER while 50% TSER only for the OEM20.
BTW, when comparing heat rejection, look at TSER instead of published heat rejection. This is more objective and is pretty standard across all brands.