I have several Mika square cut holsters. I've not tried the round cut to find out if there is any difference, but I've not had a problem with the square cut in any of my pockets. The material seems durable, and the cut of the holster helps hide the shape of the gun. If anyone did notice something in my pocket, it would look square like a wallet. Also, Mr. Mika is more than accomodating. If you have some issue, or would like a holster tailored to your specific needs, he is more than willing. His customer service is excellent. Pictured below are two square cut Mika holsters that I use for my 642. The one on the right is Mr. Mika's standard 642, square cut holster. The one on the left is a 642 holster that Mr. Mika cut higher specifically to my specifications, so that all metal would be covered by the holster. He did this for me, for free. He sent me the first one, and when I sent him an email inquiring about a second one, cut as described, he did it for me at no cost. He is currently working on one for my SP101. He actually completed the one for the SP, and I received it last week. I had a question for him concerning the cut of the holster, and he said that he would make me a second, cut slightly different. Again free of charge. You can't beat his service, as far as I'm concerned.
I've also tried the Uncle Mikes, and I use a Galco Horshide Pocket Holster for my G26. The Mika is superior to both of them. Of the three the Mika prints less, allows me to draw the gun the easiest without any manipulation of the holster, holds the gun stationary, doesn't shift in the pocket, and allows me to reholster the gun without pulling the holster out of my pocket. The Mika will also protect your gun from sweat very well, and shouldn't retain moisture.