I've personally never had a problem with the 135L and camera blur. With newer bodies like the 5D MkIII and 6D, you can crank up the ISO when needed. 'IS' definitely handicaps you after you've used it for awhile. It starts making you not think about shutter speeds as much, which can be dangerous when you go from shooting static to moving subjects.
Regarding the 100L, I've had both and the bokeh from the 135 is much better for portraits. Not to mention there is something magical about shots at F2 and the 135mm length. Of course the macro is more versatile, but I'll take the 135L any day of the week for portraits