While I continue to buy, test and try every primer which makes me curious, there's only one product which stands by me in the meantime.
Milk of magnesia.
Yes, as a primer.
Bless that life-changing day when I discovered this manna from makeup heaven.
I play around with primers on a daily basis but there's only one I trust with my best looks.This stuff doesn't play.
There are literally hundreds of websites, tutorials and bloggers who swear by this including me.
Remember Caribbean Girl Struggles? This solves it. Milk of magnesia holds up in the wettest, hottest. driest, most stressful, most humid, most shabby conditions like you just stepped away from your vanity at 7am.
This works so well for me that I can't use it to test out new foundations or concealers. It cheats. It makes everything look good.

I don't use it daily; only when I need some extra support because since it wasn't meant for skin, I don't consider it ideal for daily use...for years...
According to skincare.org, the magnesium hydroxide can be used as an acne mask. It also says that the alkaline nature which mattifies can also disrupt the acidic balance of the skin.
That said, my solution is this:
I mixed milk of magnesia with pure water in a spray bottle and just spray it on my face when I need it. I mix it with water to dilute it a bit so I don't use the full strength on my face. I'm ok with doing this because I don't use it daily and it's watered down.
I use a silicon-based primer on top for smoother application.
I have never had any bad experiences with this and I really do swear by it. It is the only 'primer' which can take me from 6:30am to 8pm without blotting.
Seriously, if I never blot it, it has a very slight dewy, natural look. Since I like the matte look, I tend to blot just once about the time I refresh my lipstick/lip gloss/hair etc.
What are your thoughts?