What the heck, I don't have anything pressing to do so I'll throw in my 2 cents on the subject. Be advised that you should take this with a grain of salt, as momma claims I'm a little more full of crap today than normal.
If you have a choice, go with a real constant reading gauge as opposed to a dipstick where you have to stop and bend over to press a button to get a reading. Too many of those dipsticks, of the various designs over the years, have had problems. The latest ones that also read the oil level sounded like a great idea at first, but I've heard several complaints about those as well.
Now, as to the need for any kind of gauge, I don't think a real need exists. First, how many of you really know what the safe limit is for the oil you are running? Second, what do you plan to do if the reading seems too high, shut her down and walk home? Why drive yourself crazy adding another gauge that will cause you to obsess and worry about another thing on your Harley that you really can't do much about anyway? Just ride the bike, and if it gets too hot you'll know about it when the temp management system kicks in.
Jerry