Well, I don't particularly favor either style for my personal wear, but I can see why people might like the Utilikilt and not the Sports Kilt.

From the Sports Kilts I have seen in person, I have not been impressed with the quality, either of the cloth or the construction.

The utilikilts I have seen people wearing, on the other hand, look like they are very well made.

Also, the Utilikilts aren't pretending to be anything other than what they are. The Sports Kilts seem to me to be trying to imitate a traditional Scottish kilt, and not doing a very good job of it.

It may come down to aetsthetics, but to me there is a big difference in a man wearing a kilt and a man wearing a skirt. The Utilikilt, though different from a traditional Scottish kilt, still looks like the former. The Sports Kilt, whenever I have seen it worn, looks like the latter.

Just my opinion!
Matt