I prefer the HALO style. only because I like to mock it all up,,,tack the halo to the main roll bar,,,and then lean it forward, So that I get COMPLETE penatration all the way around the tube.The front legs come up from the bottom,,, and you can see all the way around the joint,,,,,so you can weld it. I'm not crazy about the ol' Hail Mary method. Ive run my finger across many a 'traditional' bars and couldn't fell the weld on top,,,,between the bar and roof. Truthfully,,,,I've always said the best way to do it is to cut the roof off the car. But most of my clients prefer the halo/lean it method.
Good Luck, Rick