I've had much the same questions recently and here's what I've found the options to be for casual:

1. A traditional kilt made out of some other material (PV, light wool, acrylic) with or without pockets (high rise waist). Usually off the rack sizing so it won't fit like a custom tank. This seems to be a pretty common option. I'm not sure what the PV material feels like. They look pretty much like traditional kilts, with machine sewing & lighter materials. Can be pretty inexpensive, but sometimes that means cheap. USA kilts, Freedomkilts (pocketed models), scotweb, stillwaterkilts and quite a few others have models.

2. Casual tartan or solid color kilts, there are both off the rack and made to order options. Scotweb has some examples, as does USA Kilts. Low rise (fitting at a jeans waist.) Can be made out of a wide range of materials from 10-12oz wool, PV, acrylic etc... PV of this style seem to be lighter than MUG options. They usually don't have pockets and have a more traditional look. The equivalent of a good pair of slacks/khakis.

3. Non-traditional kilts, utilikilts, alphakilts, Freedomkilts cargo model. These vary in options and are often off the rack. They tend to fit at a jeans waist (though freedomkilts gives you plenty of options.) Materials can vary, often a cotton/synthetic blend similar to most slacks. Often have pockets, but can look like cargo pants unless the pockets are internal. I've got two utilikilts and they're great, but pretty warm. I like the simpler look of Alphakilts. Generally the equivalent of cargo pants or jeans, though there are one or two dressier models.

I started wearing a kilt with my tank that I bought for my wedding. Later I got fat and bought a utilikilt. I'm getting skinnier now and am looking at going kilted more or less full time. I like the low waist for working outside, child care, etc... as it makes bending a bit easier. A high waist can feel like a girdle sometimes. I like the snaps on my utilikilts for ease of putting on/off as opposed to models with straps. They're great for just messing around. Though I find the mocker model very warm in summer, but I tend to be warmer than most people around me.

My list of ideal kilts for all occasions for me would be: my tank for dressing up, an alphakilts aberdeen model (since it has clean lines and no cargo pockets) for daily use, a freedomkilt cargo model with slash pockets and no cargo pockets (to replace slacks), and a casual tartan kilt in my clan tartan for going out & hiking since I don't like pockets while hiking (internal kilt pockets often have your wallet bouncing around your inner thigh.)