Both Radiesse and Juvederm are capable of producing excellent and natural looking results. The choice of filler really depends on the objective of the treatment. Juvederm is a hyaluronic acid filler which hydrates and augments tissue. It is ideal for lip enhancements as well as wrinkles.
Radiesse is made of calcium hydroxyapatite particles which allows it to provide a greater degree of firmness and support for designated treatment areas. It is ideal for filling creases and issues that require more structural support (e.g. jowls, undereye hollows and even corrections on the nose)
Side effects of Juvederm and Radiesse include slight bruising and swelling. And some patients may experience allergic reactions to hyaluronic acid. With Radiesse, there is also the potential for lumps to develop. But this really depends on the skill and experience of the practitioner.
Web reference: http://www.finetouchdermatology.com/los-angeles-radiesse/