Unless you are going with a rigid box type then a Carboard bike box from your lBS works a treat. Much easier to pack/protect and probably stack in the hold. They have always done better then my bike bag did.
Evoc – cost a lot but I certainly haven’t regretted it. I’ve done cardboard boxes and cheap bags but the Evoc got my bike to NZ and back (via a few stops) with the bike untouched. The bag took a fair battering but survived well as well. A LOT easier to pack too as it’s phenomenally well designed.
+1 for the Evoc. It’s much faster to pack/unpack than using a cardboard box, has decent wheels (big help when going through airports with a suitcase and carry-on as well). Protection is good to (for a soft case), just use some pipe lagging for extra peace of mind.
I used a cheapo bike bag from a mate. Think it was called World Bike Bag or something. A mate had the Evoc bag.
I wrapped my frame in all the bubble wrap and Corex I could lay my hands on. Removed the discs from the wheels. Used a separate wheel bag for the wheels.
They both did the job, but my bag was pretty hard work to roll along and carry on the train. So much so, that I found myself wishing there was a hire service for the Evoc bag.
Having said that, my mate has found some of the stitching on the inside of his Evoc starting to deteriorate. Should get fixed with little problem though. Wouldn’t get a cardboard box because of the hassle of transporting it on a train.