I have been lucky with luggage/skis on European ski trips (5) - no delays/losses. The trips have been either on United/American from SFO to either Frankfurt onto Geneva, Newark onto Geneva, London onto Geneva.
West Coast/Canada I have never had any issues with destinations like Vancouver, Calgary, Anchorage, Jackson, Spokane, Montrose, Aspen, Kalispell, etc. United has even put my luggage on earlier connecting flights home to SFO - so I have filed missing luggage reports only to find my bag came in an hour before me. (This record would not stand if I brought skis to Telluride. United purposefully delays skis on full / small prop plane flights from Denver to TEX/MTJ (or any small ski destination) due to weight restrictions.)
My only ski bag loss has been on Southwest - flying to Albany to meet friends local to Lake Placid/Whiteface. They sent my bag to Providence for 2.5 days. However, I was able to rent some demo carving skis - and purchase about $500 in gear. I still had a most everything in a boot bag roller that I always carry on. Southwest reimbursed $700 and gave me about $250 in flight delay coupons - after carefully documenting all the calls/emails/receipts.