I already have two Scrubba Air Sleeves, one for my MacBook Pro and one for my iPad, from their Kickstarter campaign. I purchased this for a friend who just got his first MacBook.
The reason I came back? Because the Sleeves have been proven excellent products! They protect really well my electronics, they do become comfortable pillows (really useful, especially for long flights), they are durable and stylish.
The Shoulder Strap adds an extra level of comfort if you want to carry the sleeve as your main messenger-style (but compact) bag. It attaches and detaches easily, but with secured clips, so accidental removals are virtually impossible. It's also easy to adapt its length for your optimum size.
To be honest, the Cable Pouch is the less useful of the products for me. Yes, it's smartly designed, with internal cases/ compartments for putting you charger and cables, but when attached to the Strap the whole set loses a lot of its style, and some of its usability, as the pouch isn't exactly secured in one place over the strap, it's somehow floating. However, I've found that the Pouch can be placed inside the Sleeve, without it becoming very bulky.
The shipping was fast and within the timeframe given, as with all my previous orders from Scrubba (I own some more of their products).
I highly recommend the Air Sleeves and I think that having a Strap and a Pouch provides more flexibility and options for using them effectively and in style!