Traction
Being a winter ski tourer, the idea of having a G3 climbing skin for traction in snow on the sole of the bootie seemed like a neat idea. Once I saw my dog running around in them, I wondered why the obvious downside of this had not occurred to me. Climbing skins are designed to grip in one direction, and to glide in the other direction. This meant that my dog did enjoy increased traction when going up hill, but going down hill, or skidding to stop for a sniff/pee/toy, or generally playing around meant that the dog was sliding around like crazy. All dog booties can be somewhat slippery in some conditions, but the skins seemed to give extra glide with forward motion. In some conditions I actually took them off the dog for safety.

Other than that, the boots performed pretty well and stayed on well compared to some other products tested. They were well made, and easy to put on. I think using stretch Velcro (instead of static) for the closure would improve comfort and security of the product. Snow did pack up the tongue area, but the booties generally stayed on and were not full of snow.

On trail
The booties stayed on well, and if you are leash walking a slow dog, they should not be too slippery and might provide extra traction. They offer adequate protection against salt, but rinse after use if heavily saturated with salt.

Off trail
The rating here would be much higher if it was just about how well the boots stayed on in various conditions. However if the dog is running off leash, the boots are very slippery in one direction (sliding forward with forward momentum). This makes them less than ideal for off leash play.

Comfort
The dog seemed to find them comfortable and did not fuss at them (once used to wearing them). You have to do the Velcro closure up VERY tight, right above the bend in the wrist, so check for chaffing with long-term use. These are sold in pairs (of two) so you can order different sizes for front and back paws.

Value
The price seems fair, considering nice ergonomic design and good materials. If you loose a boot you can order just two since they are sold in sets of two instead of four. (2 for $25.)

Durability
These are made with nicely durable materials. They stayed intact during testing period and did not show signs of wear. Expect some wear and tear if used on sidewalks only, but they should certainly last the season.