I just returned from a trip to WPC 2015, and for the first time since I acquired the HP Spectre x360, I left it at home this time. I opted, instead, to take along the Surface Pro 3. And, the Spectre was sorely missed - primarily the better battery life and display.
My primary reason for leaving the Spectre this time is because I've yet to find a bag that fits it and still has adequate space for my carry-on accessories. The weight difference between the Spectre and the Surface Pro 3 is nominal, so it's not about that.
When I returned from WPC, guess what was waiting for me? The just-released Vitesse Messenger bag from Waterfield. Waterfield bags are pricey, for sure, but they are clearly the best bags in the world. The Vitesse Messenger bag starts at $159. Add a bag strap or one of the new Cycling straps and you could pay a total $169.
I've not had time enough to fully review this bag yet, but wanted to give you some initial impressions. I have another trip coming up in less than 2 weeks, and will definitely be using this bag to carry the HP Spectre x360 with me. And, based on the bag's capacity, I may actually be able to carry both the Spectre and the Surface Pro 3 and much, much more.