I have been traveling with my Stormcase im2500 (Pelican and Stormcase merged years back, but they're more or less the same size/function case. I like Stormcase's latches better, but otherwise, pretty synonymous.)
The absolutely waterproof thing is nice - whether than means liquids leaking OUT, for when you bring that bottle of wine home from Paris, or liquids leaking IN, like when my tarmac stop in Orlando SOAKED everyone else's luggage to the core.
I often use it as a carry on, but have ability to truly lock and TSA check firearms in it if I happen to pick something up when I'm out in the world. It's not uncommon for me to fly somewhere carry-on only, but then fly back with ammunition, firearms/parts, etc. It's nice to have the option. The wheels on PeliStorm and the warranty beats any small rolly luggage I've ever had.