after i installed mine I didnt get 15' down my driveway before i noticed the difference. the front end felt much more solid going over little bumps and dips. when the tires travel over uneven terrain the car feels more planted, and when turning into sharp corners (like during an autox) there seems to be less understeer.
i think whoever wrote the review that you read, either has no sensitivity towards the handling of their car, or they wrote the review only to shine negative light on the frame locks for some personal reason
but yes, i've heard the frame locks can increase the damage sustained by your car during a front end collision. they basically lock your bumper support to your car's chassis in which you theoritically lose your 5mph buffer and increase the sensitivity of your airbag sensor. In actuality though, i already had a front end collision with mine after I was rear ended in traffic and pushed into the car in front of me. It was hard enough of a collision to do moderate damage the front bumper of the car that hit me, knock everything in my cubby onto the floorboard, and give me whiplash for 2-3 days. Surprisingly my airbag did not deploy and there was no damage to my front end other than some scuffs on my bumper. Myth busted?