I mainly stick to riding the one trike for all my needs
Sliding etc.. being less of an issue on three wheels and I find that rough/loose ground is little of an issue, although I get no ejoyment from "hacking" through mud and stuff so generally avoid such conditions anyway.
I do have a folding Dahon hybrid type bike with 26" whhels however for when I travel by train as I can take it with me easier that a trike and still enjoy a cycle around London, it is damned uncomfortable after the hammock seat of the trike however so I use it very little, still it's nice to have the option.
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Buck
I would rather be out on my Catrike
http://www.catrike.co.uk