But it is perhaps the most competitive niche of one of the already most competitive markets in the country.

Does the Biggerpockets community have a preference for window brands for flips or long term rentals?

I trust no one and prefer to self manage. 

@Micaiah CormierScrew That hard money lender with their high rates is Get the owner to hold the note for as long as possible and Avoid -any -balloons if you can .get the interest reasonable preferably 5-7% fixed .

I prefer B- / C+.

I prefer adding value to my properties, and I can’t do that with stocks. 

I think if most flippers are honest (10-years later looking back), they'd prefer to still own those homes as cash-flow positive rentals.I don't remember where I heard it (so I'll attribute it to MLK or Abraham Lincoln, maybe Warren Buffet) - "You can get rich flipping houses, but you get wealthy keeping them as rentals".

Others prefer individually picking vendors one at a time and building a more complex but also more specialized team.

I would prefer 4 doors in one property making $14,000 a month versus 20 doors with an average rent of $700 each (presumably across 5-10 separate properties).

That is the preferred method.