If you're tapping 1/2 inch and 5/8ths on a Bridgeport or Bridgeport clone, why hassle with a tapping head? I've tapped hundreds (probably thousands) of holes on a Bridgeport with the tap tight in a drill chuck. With three phase power, the motor instantly reverses when you've reached the correct depth with a flick of the switch.
Tapping heads take time to get the mill set for them, as you normally have to lower the knee, because of their increased height. In some applications you run out of daylight under the spindle. In a shop doing production, every minute counts, I HATE having to raise and lower the knee any more than I have to.
I have Procunier tapping heads, tapmatics, and Bilz holders. The Bilz are the most compact, and tend to be the ones I grab. I have three sizes of Procuniers, that are clutch driven and have a higher retract speed. They ARE nice, but because of their bulk, I rarely if ever grab them. I tend to ONLY use tapping heads on small taps, as they are so easy to break. Another brand of tapping head is SPV which are made in Sweden. These are very nice heads that have built in adjustable clutches. I use these MOST of the time in my Sip and Devlieg boring machines. BUT for the fastest drill and tap, in the 1/2 inch and 5/8ths, my go to is a Bridgeport with NO tapping head at all.