I think dog boots are like people boots; what works on one foot won't work for another. I've tried several different brands and here is what I've experienced with my lab.
Ruff Wear are cool with their Vibram soles, but can be the most confining on the foot so fit really matters. My dog really did not like these because of the confinement. I'd use them for hazardous areas with sharp rocks or thorns, but gave up on them for winter. They were most expensive too.
Next I tried Muttlucks (in yellow in photo). The faux leather bottoms provide some good protection and are more flexible, so the fit is much better. These work great if its cold and Im walking my dog on hard surfaces (protection against cold and chemicals/salts). I found that when my dog ran through unpacked snow, however, snow collected inside that black cuff and formed a ring like a donut around his ankle. 5 minutes in deep snow and he's biting at his ankles. I sewed some velcro to the top of two of them to try to keep snow out, but the jury is still out on this.
Last I tried some unbranded simple fleece square boots that are sold at a nearby dog shop. They have a plastic/vinyl bottom and different color velcro's for different sizes. These are the cheapest (about $5-6 per boot) and generally work the best so far.
So for me the cheaper and simpler they have been, the better they have worked. Cheaper also means you can buy more of them. If you go camping or extended day hikes, they can easily get wet and then are no good - but if they are cheap have some back ups handy. On that note, I'll toss out one more brand for you to consider -
Kondos up in Ely. . They make an even simpler heavy nylon boot for dog sledders who only want enough to keep the snow and ice chunks from getting between the toes. They are really cheap, especially if you buy in bulk!
Lastly, and slightly off topic, when my dog has been running in snow without boots and gets somewhat sore in between the toes, I use Musher's Secret - a waxy paste that helps protect that inner foot. Also tends to both protect against and heal up sores from road salts and chemicals.