If you're looking for a DSLR then I'm sure the 550D will be more than adequate. I don't know anything about the other camera however, the important part of close up photography with DSLR's will be the lens you use. If close up photography is what you want to do, then you should invest in a good quality Macro Lens. These lenses are specifically designed for close up work and give excellent results in picture quality. I use a Canon 60mm Macro lens which cost around £350. I think they're around $400 if you're in the USA. You can get macro lenses up to 100mm so you don't need to get so close to your subject but these are of course, more expensive.