I've not handled the colibri before but I have handled quite a few Muelas and own one as a using blade.
Muelas are generally pretty impressive blades for the cost. Well balanced, good steel (most are normally 440c). Fit and finish are good. I don't think you will go wrong if you are looking for something a little different. It's not popular in the States but lots of people in Europe, Aust and S. America use them I gather.