Do you love big bluegill?
Ive only tried but one of these underspins, myself. It wa s Zebco and I liked it a lot. I do recall that it was wound with very light line, and I believe that makes a difference. I know a few fishermen who swear by them, and they do alright.
I love underspins because they only need one hand to cast. That means I can be grabbing my other rod at the same time.
I find the trick to a smooth reel is to clean all the factory grease out of it and then use some quality reel lubricant. I own two Zebcos and two Shakespeare underspins
This is something I end up doing to every reel I own - breaking it down and lubing it up. I don't really do it on purpose, not in that I have to. I just do.... mostly because I like to know how their innards work.
I use a special grease, a silicone based lubricant I get from work. For all the shafty, go-roundy parts that need a little drop of oil, I've got a light, silicone oil in a dropper. Both of these are intended for use on pharmaceutical equipment, so they are food grade rated and non-petro based.
But plain old automotive grease and 3-In-1 Oil works about as well. No need to buy special stuff, unless you want to.