I haven't bought racing flats in years, nor have I read any reviews. So I'm a "clean slate". On Sunday, I went to the local running shoe store and tried on all the racing flats. They let me run around outside on the roads with each of them. Here's what I found:
Nike Luna Racer: feels like a mushy house shoe. And the soles are too wide - they feel like platforms.
Brooks T6 racer: These are the ones I bought. They feel like the old Nike Kennedy track spikes converted to road racers (which is a good thing!). I couldn't help but run fast in these. They fit my feet well and most importantly, I hardly noticed them as I ran. I'm not sure if I should go over 15k in these shoes, though. They will be perfect for road 5ks.
K-Swiss K-Ruuz: I liked these but I'm not familiar with the K-Swiss brand. They seemed to offer less support than the Brooks T6 racers even though the T6 racers are the lighter shoes. So I would only recommend the K-Swiss for short road races.
Asics Gel Hyper Speed (can't recall which #): These felt like cheap shoes to me. Also, the toe box is too big for my feet so in order to tighten the laces sufficiently, I had to "bunch up" the fabric on top of the toe area.
Saucony ProGrid Kinvara: Too soft. Lots of energy is lost in the marshmallow-like landing.
(Tester: Former D1 guy who still races roads. 5k-14:15 mile-4:06 with neutral pronation. Size 10-11 (depending), 5'9 140lbs. I have no affiliation with any brand, and no sponsorship obviously.)