Not on a psu. But where I work we use a lot of it and throw a lot away so I get it free and I use for lots of stuff. It can be as neat as you want it to be.
EDIT: Also, some heatshrink has glue in it which cements the tubing on when it's heated. With the glue, you can get smaller heatshrink, half-inch and slit it open since you can't get it around the molex connector. Then when it's heated, it won't go anywhere even though it's just a rolled sheet. This may even work without the glue but it could fall off with a lot of flexing.