I use the WJ Surge Pack. The pack is excellent and well thought out. The magnets in lieu of the zippers is a fantastic option for me because I wear it as a fanny pack and reach into it alot. I don't have to swing it around to unzip or have any issues trying to open zippers around my back. At first I was concerned about the magnets, but they're strong enough to not open accidentially.

The side pockets are actually very handy. I don't load 'em up but I do have some items in there that I need to reach quickly. I use them more than I thought I would.

Size wise, it's large enough for four medium size C/F boxes and incidentals. In the winter I put three C/F size boxes in it, with a spare hat and set of gloves, along with incidentals, snacks and it's not too full. There are straps that I use on it on the bottom of the pack that allow me to remove a layer, roll it up, and strap it under the pack - another cool feature.

I wear it as a waist pack, but it can be worn as a chest pack and has an extra strap that goes around your neck. I wouldn't consider it a sling pack but it could be worn up and away if needed.

It's not waterproof. If you fish in a driving rain all day, your items will get damp but not soaked. I treat it as well so it repels water and it is lined inside. I have dunked it by wading too deep and it didn't fill with water; but it is definitely not waterproof.

Can't live without water bottle holders on my packs and it is easy to reach back and get them without any trouble and replace them without any trouble as well. A plus.

As you can tell, I love the pack. I agree with Dave, go try them on and fill them with what you want to carry on your standard days as well as what you might need to carry on your heavy days and see how they feel.

Cheers,
Mike.