This was my first bag and is also my fave. I haven't treated it with anything but I am careful of where I set it down. If you look after your bag you should only get minor marks which will hopefully blend with the patina over time.
Umm well I have the black and my vachetta on the bottom is great. I don't think I even have any stains?!? I even set my bag on the floor of restaurants (Don't kill me! LOL). It will be fine but the more you worry about it the more it will probably get messed up! Truth is who is going to see the bottom of your bag anyway?!! I mean it's a bag that stands on its' own. JMO!
I have it in white. The third time I took it out, I got a big blob of bbq sauce on the bottom of that virgin vachetta. I cried. My husband felt so sorry for me that he called our SA and asked her what to do. She said to get saddle soap and apply several times until it was less noticeable. It did the trick. You can still see where the stain is, but it's much less than it was. The saddle soap helped to darken the vachetta a little. Plus, it seems to make it a little waterproof, too. So, don't take it to a bbq restaurant and don't worry about it. I was so paranoid about it I'm sure that's why I got the sauce on it. I still love that bag. Now I take it everywhere and I don't worry about it at all. I obsess a little over all my new bags until the "new" wears off. Get it---it's an absolutely stunning bag!
I wonder also, if I will be good with an Alma due to the Vachetta. I love the MC Black Alma, the MC White Alma is growing on me a little lol. I think I'll be one of those who worries about the bottom getting stained. But I'm in love with the MC and Mono Alma.