Does anyone use the retractable spiked tri-pod feet? I was looking at getting a set, but was wondering if the dirt and muck we so often find ourselves in will render the retracting useless.
I've got the Induro C414 that came with both rubber and spiked feet. I use the spiked feet regularly on lake ice when shooting water fowl and eagles out there. The rubber feet will slide around no matter what you do while the spikes hold the tripod nice and steady. Otherwise, I keep the rubber feet on, since I don't have movement issues on any other surface... yet.
Like you, I'd be a little worried about retractable spikes, since I quite often getting into mud and sand with my tripod. I just really think that the mechanism is likely to get jammed up. Changeable, screw-on feet, like with the Induro are very quick and easy to swap out, taking only a little longer than it takes to fully open the tripod. I keep my alternate feet in the bag that came with my Induro and generally keep that bag in the trunk of my car. Swapping out is not a big deal at all.