Lens optical quality is usually the minimum factor for a camera's image quality. Canon's interchangeable lenses have long been great performers, but, advantaged by new lens designs made available by the optimized RF mount, the RF mirrorless camera lens lineup is nothing short of awesome. RF lenses outperform all other lenses in their respective class in nearly all circumstances.
During a conversation with Canon engineers at a press event introducing the first Canon R-series full-frame mirrorless interchangeable lens camera (MILC), all RF lenses were promised to have advantages over their EF lens counterparts. Potential advantages include smaller size, lighter weight, and new features. The Canon engineers indicated that RF lens image quality would be minimally equivalent and often better than their DSLR lens counterparts. The reality is that we see the "often better" advantage appear more like almost "always better", with many lenses delivering simply amazing image quality.
RF lenses with the "L" in the moniker and a red ring represent the ultimate lenses available, delivering the outstanding image quality serious photographers seek. These lenses also feature impressive physical performance, and they are built for the rigors of daily professional use.
The non-L series RF lenses are lighter and more affordable, but still, they provide excellent image quality and performance.
Canon's support system (in the US at least) is second to none. If you have a serious repair need, or simply need help using your camera, Canon is there for you.
From the beginning, Canon's RF mount lenses set the image quality bar very high, and the other features of these lenses, including AF performance and image stabilization performance, are outstanding. Most of these lenses alone justify the purchase of a Canon R-series full-frame MILC.