One of the features that first attracted my group to slic3r was the ability to do infill every other layer (or less). This allowed finer outer layers while not delaying print speed very much. Worked great and we used is on almost all of our prints.
Unfortunately, this using this capability now leads to a nasty bug. If your part has slanting faces, or various other sorts of "interesting" geometry, then any rate of infill, except every layer, causes extra infill to be added to layers that should have none. This causes plastic build-up while printing and eventual failure of the print when the nozzle collides with the build up.
This problem is fully described, with examples, here:
Slic3r Issue
What experience have other folks had with this? Is it a real problem, or are we doing something else wrong?