I'm starting to think the "103 12cm case fans review" article (available on your nearest interwebs) was sponsored by Enermax!
I don't think so, but there's a whole collection of nonsense data in that ranking.
According to them at 7V the Twister Pressure at about 1200rpm has the same noise level of the Noctua S12A & Scythe Slipstream while running around 750rpm... or what about the worst fan noise outcome, 54 dB, from the iPPC 3k at around 1600rpm when the SP120 HP from Corsair at around 1300rpm sits 20dB below that (twenty dB!)...
...summarizing, personally I don't care that test, at all.
The HP-12 PWM looks interesting. They seem to cost around €20 each though, which is a little more than I'd like to pay.
It's an high end fan: it sports the 2nd gen of the original Matsushita FDB bearing, paired with precisely machined blades and an high quality heavy frame, so that it feels so peculiar when you get it in your hand the first times. I paid mines 17.50 euros/each last year, now I see them at 19.50 from the same source (alternate).
I'd be very interested in hearing your opinions on the enthusiastically named EK Vardar F4-120ER, after you get to test it further. They seem to be around €20 each again though, which makes me think I should just go for some EOL Gentle Typhoons!
I paid mine 17 euros/each in december (still their current MSRP) for a watercooling setup now in stand-by state: I don't think I will play with them before next may.
The Gentle Typhoon could be an option as well, particularly if you already know them: their noise signature is somehow an hit or miss, here at SPCR some love them and some do not.
The nice think about the Flex fans is I could snag 2 for about €20 total, and I trust Scythe as a brand after all of their previous successes. Do you have any personal experience with the Grand Flex?
I can't help on 2k Grand Flex: the 1,6k I know a bit more were just below-average/mediocre fans in my experience, either the Glidestream or the Slipstream are noticeably better at any speed.
But those were low pressure fans, that other one was not.
Said that, I'd add: buy them. Just that.
First hand try is always better than anything else: if you need reliable bearings and high airflow, give them a try and, if anything, re-sell them.