After looking at all the positive reviews about mk3 sneakers, I am betting on mk4 shoes. Also a great choice, ready to go, waterproof, great on the track. I also take my dog to the park, the spikes are not too uncomfortable on the carpet, the only downside is that they have to be removed at some point. Update, after about 6 or 7 rounds they started leaking, the last 2 times I've had wet feet, the shoes are coming back, too bad they're really comfortable.