Why I use a backpack style bag
I use a back pack because I was broke when I first started playing and just carried the discs I had in that. My step dad gave me one of those techie backpacks with all the little pockets and thick straps. I found I could fold/tuck the zipper flap when it was fully unzipped, and it would leave my discs exposed for easy access.
There is a laptop sleeve that I have modified with some safety pins that hold 2 putters up away from the other discs.
It stands up when set down, and there is a nice sturdy handle at the top. Easy to grab for upshot walks/post putting. I will pop it over one shoulder or both depending on terrain/weather. Padded on the back, thick padded straps, and a waist cinch should you get adventurous and jump over a stream
Depending on the ratio of mids and drivers I can easily fit 20 discs, including the two putters. I can fit a 32 oz drink, and have plenty of pocket space for cigs, wallet, keys, phone, snacks and I have a towel on a quick release.
Last and most important; it was free! I have a monster bag on the way that will be my new tourney bag, but this has lasted 3 years no problem.