I have to chime in here and will try and post some pictures later. I have a Series 0 Aluminum space gray watch. I got it on release day in 2015. A co-worker of mine told me to go with the SS strictly due to the sapphire glass but I simply couldn't justify the cost.
Fast forward to today - I don't know if I would ever buy another aluminum watch again. I can live with the casing getting scratched as 'wear and tear' however, the glass on my watch is pretty much destroyed with scratches. Inside, I notice it...but I can live with it. However, go outside, in the sun...good luck seeing anything on the screen.
For the simple fact that the SS models have sapphire glass alone - I'm going SS. I keep second guessing myself about swallowing the cost of the SS model but then I look down at my Ion-X glass and know I will have
zero regrets.
Side note: I work in IT. My day-to-day is not very rugged or demanding (ex: construction). My first scratch happed while at an aquarium. From there, I began losing count.
[EDIT: Pic posted - And there are still others that i couldn't get to show up in one shot via one angle]