I’ve got the K-edge one, that looks similar to the raceware one. With a 50mm stem the garmin mount actually sits pretty much in the middle of the bars (i.e. it’s almost 50mm between the centres of the two rings). So, the computer will be in the middle, but almost as far forward as if you’d mounted it on the bars.
I’ve also got the SRAM one mounted backwards on another bike (with a 60mm stem) and that puts the mount almost on top of the stem cap, so a fair bit further back than the k-edge/raceware options.
EDIT: Actually, looking at cnud’s pictures I think the raceware is a tad shorter than the k-edge (due to the lack of a hinge, I guess