I honestly think you should go with the Samyang. Been using the Samyang AF 12mm f/2.0 Fuji X for a few months now on my fuji setup and im super satisfied with how it performs. For hiking especially, having autofocus is just one less thing to worry about when you're tired or trying to grab a quick shot of a view. The weather sealing is a nice bonus too since Glacier can be unpredictable. The TTArtisan 10mm f/2.0 ASPH Fujifilm X is definitely wide and cheap, but manual focus can be a pain if you arent used to it yet. Honestly the 12mm is plenty wide for those massive mountain vistas. No complaints from me on the image quality either... it basically just works well without breaking the bank. Good luck with the choice, you're gonna love that camera!