3/8 inch drive torque buying advice

Out of those three, I'd get the Teng Tools one.

I don't use those old deflecting beam type torque wrenches, they are useless. But, the ones I like the most are the ones that have a pin that pops out when the desired torque is reached.

for doing head studs etc!, stick with your 1/2" drive, 3/8th will be getting near it's max settings - and none are accurate at that end of the scale
not sure why the above poster says deflecting beamare useless, they are by far the more accurate, they are also a lot easier to check that accuracy and a lot easier to use - a 400mm torque wrench requires a lot more effort than a 650mm, hauling down head studs on a cummins to 150ftlb is a lot easier with an extension on the 650mm one too

torquing bolts is not so much about getting a bolt to prescisely 85ftlb and more about getting all the bolts.nut,studcap to the same value ( issues don't arise if they are only 75 instead of 80 as long as they are ALL 75) warped heads binding big ends etc - if they can be blamed on torque figures - are caused by uneven torquing
Of the 3 you link to, and for the likes of a briggs head etc I'd grab the teng, it will manage the mower, maybe the head and barrel on a bike ( light ali motors ) but I'd never use it on a car or truck motor

We're going to have to charge you $5 for the advice because you haven't bought anything off us.

I've had a Teng like the one you link to for about 5 years. Quite satisfactory and would buy another.

DON'T buy the Powerbuilt - I bought that exact one and it feels really cheap - like a toy. The Teng is not much more but feels much more solid, really wish I bought it at the time