Definitely go for the Muni to learn on!
I was in your exact same shoes as few weeks back–I wanted to learn the Unicycle, and I was deeply into the idea of getting a Muni because they seemed to be highly versatile, and really strong. I knew I would be falling a lot, so a good strong Muni seemed to be the way to go. I figured, why get a cheaper uni to learn on, when it stood a better chance of breaking due to the abuse I would give it as a learner.
I opted for the Nimbus 26 inch (with that monster 3 inch wide tire) and sure, it is not easy, I’m still getting the hang of it, but when that baby takes me along those highly satisfying fifty-foot excursions into the abyss, it is well worth it.
Another advantage of a Muni is that even when learning, you can opt for non-pavement surfaces. I progressed tremendously by riding from tree to tree in a gravely-dirt park when the local parking lot was too full of moving cars. Also, concrete pavement can intimidate the learning unicyclist, and a Muni allows you to ride on softer surfaces like packed dirt or grass where the idea of falling seems a lot less dangerous.
There is also another reason I decided on a Muni as a first Uni, and it’s both important, and pretty damned silly. I just think Munis look really really cool. I mean, if I’m going to be out and about in public doing something as absurd as balancing myself over a single-wheel, I might as well do it with a bit of style, eh? A scratched-up Muni with a fat knobbly tire has that and a lot more…
Munis are totally punk rock. Munis are also quite heavy metal. They really rock, even if you stink at unicycling as I admit I currently do. As bad as I am, I just can’t wait to get back on the damned thing, and I think this has a lot to do with my uni being a muni.
Plus, you get less “clown” comments with a mean-looking kick-ass Muni. At least I think you do…