I've played across the whole spectrum of character power and I've generally found low levels of power (what people often call "mild powers") to be the most challenging and the most enjoyable. This is by and large for the simple reason that limitations breed creativity, much as necessity is the mother of invention. If I tell you to draw a line from point A to point B and give you a blank piece of paper, you'll draw a straight line. If I give you the same instructions but with a maze -- that is, limitations of where and how you can draw your line -- now there's a challenge involved. The same largely applies in roleplay combat. It's why it takes less effort to shift a character up in power than it does to shift them down: down-shifting requires applying harder, more concrete limitations.
That being said, I did enjoy high powered combat when I played it, especially with the DBZ approach of just "fuck it, laser beams for everyone!" There's nothing wrong with it. From a competitive angle and ensuring that characters can be placed on as level a playing field as possible in tournaments and similar events, I prefer mild powers. I (as Melon knows) even prefer the additional limitation of making fights non-fatal to force people to really think about their posts by removing the option of going right for the throat, both literally and figuratively. Puts people on their heads.
Also, if you want to read about superhero regulation or lack thereof, read Ennis's The Boys. Mostly because Ennis is hilarious.