I use my NF MM's as a daily bag but started craving a GM. I bought a Mono GM recently off ebay and it's amazing! It's a perfect travel bag or if you carry a lot on a daily basis. I cinched the sides when I was on the Metro so no one could steal anything. I prefer Mono - it's true about the straps. When I first got my DE NF in the MM size years ago, I almost wanted to return it! I carried it while wearing a sleeveless top and the straps dug into my shoulder so bad. Eventually they softened up but not as soft as vachetta. I think if you plan to carry heavy things - especially a laptop, I'd go with Mono. It IS painful when you get your first watermarks or stains but eventually they all blend in once it patinas. You can always go the pre-loved route if you're uncertain about the pattern. I paid $600 for my GM- old style without the pouch.
Ooo...Mono is at 7 now

Thank you for your response and insight!! I have been looking at preloved too! All good advice!