I compared both and chose the non-flow through.
As mentioned the flow through's stick out more and weigh more.
My unit doesn't have the metal valve stems (yet) and I didn't want the weight of the flow through's hanging off my rubber stems.
The non flow through also have a removable anti-theft 'cover' that can be removed to make them even smaller and lighter. I did that and added the metal stem covers SOLD HERE
to make them stable. Very little flex now!
I would like to see more information on the specs/range of the internal ones as they would eliminate all the exterior sensor concerns (weight/theft/stick out too far, etc.) but I don't see much listed about range.
One other thing.... I see a lot of posts from people saying they bought the flow through's because they didn't want the hassle of removing the non-flow through type to be able to air up the tires. With the opportunity for dirt or water to get into the sensor, I surely wouldn't run the flow through's without a valve stem cap on them.
If you remove the anti-theft device as I did, it isn't any harder nor does it take any more time to unscrew the non flow through than it does a cap.
If the concern is theft... I am probably at the wrong campground but if so... it takes all of 10 seconds to remove them and stow them somewhere safely and saves the battery too as they shut off when removed!