Here's what Airbus says about their design considerations...
http://www.ifalpa.org/sab/03SAB002_U...n%20Airbus.pdf
Basically, it seems they've designed their tail structures to the MINIMUM requirements specified by FAR/JAR 25. Boeing by contrast, has gone beyond the minimum requirements. I've always been partial to Boeings anyways. This is just one more reason to justify my prejudice.
However, Boeing points out, that while their tails are designed to handle a great deal of sideslip stress, the engine mounts are not designed to that same level. Cyclical over yaw, may overstress the mounts. Large sideslip angles, via abrupt inputs, may cause engine surge and stall at high power settings. Reason enough to be smooth on the flight controls at all times. This does not mean, that a forward slip can't be a smooth, controlled and useful manuever. I still see no reason to remove it from my "BAG". At least on Boeings. However, those of you flying Airbus' "made of glass", may want to keep your bank limiters set to 10 degrees and ask for long finals.
"If it ain't a BOEING, I ain't GOING."