IMO, I prefer using a "MTB" shoe as the sole of it has protrusion below the cleat and allows me to walk better as well as safer. Walking up on my toe and on a slick cleat has nearly caused me issue a few times now. Even with the MTB shoes I use, the sole itself is a bit slick on certain surfaces and a part of the reason I just switched back to flats.
As an aside, what is the brand of the extension you are using and if you don't mind, what is your approx. weight?