Heard awful things about those Soma bags. From what people have told me they rip really easily and let the air out. No repair kit with them either.
I've just bought a CUrve Overstayer (the burrito closing one), and it seems quite good. There's no room for a board to move around in it so as long as you pad the rails etc, I reckon it'll be good. Not much room for other bits and bobs though!
+ 1 for the curve overstayer. Can get 3 boards in there at a push, pretty decent padding and no where near as bulky as a coffin so great for travelling around.
For air travel I think it's as much how you pack the board, as the board bag its self. I always get a slightly oversized bag and use foam Pipe insulation arround the rails and top it off with a wrap of commercial quality bubble wrap. I take a roll of parcel tape out to wrap it for the return.
Done all of that before Tim, and still arrived with a snapped board! The beauty of the Curve bag, is that it fits around the board, so there's no gap between the board and the padding, and the board can't move around inside. Off to Morocco in a couple of weeks, so we'll see how it goes!