which of these is more used by most and which do you find more effective, what helps you make the choice???

I personally use them about the same amount of time and in the same places.

I really like the Eakins Finesse jigs in Texas Craw and PB&J for rock bottom smallies. But some days the Hula grub paired with a spot remover or gambler giggyhead is deadly.

I like a twin tail hula grub on a jighead (* *).  That is a confidence go-to lure in most situations where fish are shallow and unwilling to hit more aggressive jigs or lures.  Those things work.

I should probably use a hair jig more often, but I'd have to tie my own.  I always get aggrivated with the ones I get from Wal-Mart.  I should probably buy higher quality hair jigs, really.  They work great, especially in clearer waters.

Either way you go, you'll catch fish.

I really don't think it makes much of a difference, and if it did, I'm not sure any of us could accurately say which is better in X situation.

I absolutely love using 4" or 5" hula grubs on a little weedless jighead, anywhere from 1/16 to 1/4 oz. The action on the fall is really hard to beat, and it's a great rig to use when fish are suspended in or near cover, and being finicky. I don't believe a bass can resist a hula grub slowly falling, pulsating, with both tails flapping in front of its face. The action on a slow fall, IMO, is at least as effective as the action of a weightless senko, maybe moreso. Colors? Same as a senko - mainly pumpkinseed or watermelon.