These are sturdy kraft paper bags, slightly shiny and ribbed, with integral twisted paper handles which look and feel much better than the flat paper handles on cheaper bags. You can use them as is, or you can laser-print (or digital press) your branding and stick them on. Surprisingly, this gives an even better effect than pre-printed bags (expensive) as long as the stickers are printed full-bleed, with no white edges.
We used these for welcome bags as part of a substantial rebranding project. At this size, they will take an A5 sheet of paper and various other bits and pieces, and are just about right for people to carry around with feeling that they've been imposed on. They give a boutique feel, and a lot of people have told us they love them.
The only thing which might trouble you is that there is obvious evidence of a fold, which is a result of the way this particular kind of bag is constructed and shipped. If you use the fold to line up your sticker, then it disguises the fold and gives you consistent sticker placement. However, the effect is never going to be as posh as the next level up, which is the more expensive bags with separately attached soft-cord handles.
We're now half way through our second box of 300, and very satisfied.