Decisions, decisions....! I work as a professional photographer abroad in Central America with a Canon 60D and various lenses, the one I use the most is the Canon EF 28-135mm f/3.5-5.6 IS USM, second most is my Canon 100-400.

I am considering upgrading either my camera body OR my primary lens. Body would be a Canon 5D Markii body, as a friend of a friend is selling his gently used body. But I wonder if investing in another lens would be a smarter first step. (Either the Canon EF 24-105mm f/4L IS USM or a used Canon 24-70 f2.8L).

Thanks in advance for your advice!