Six of one and half dozen of the other IMO. I have both types. The lower tap version, the tap is very close to the supporting surface so has to “over hang” in order to dispense. The lower tap doesn’t come with a float so you don’t have the option of drawing off beer from the top. The upper tap has the float that sometimes can be problematic, especially if it leaks past the seal in the back of the tap and you get a lot of gas in your beer once the beer level is below the tap. I fitted Sparkler taps that gets around that problem.
I prefer the upper tap for ease of dispensing.