My wife and I are both 67 and will be riding in the semi-bike-friendly environs of Boston and Brookline. Some local hills present challenges for our bad knees, thus our interest in ebikes as opposed to the 15 year-old city bikes we're riding now. Considering Evelo Luna (http://www.evelo.com/electric-bicycles/luna/) and the Blix Komfort+ (http://blixbike.com/products/komfortplus). We're newbies, so welcome any and all counsel you can provide. Thanks!