I have used Sparkpeople, Lose It, and Myfitnesspal (the latter two are on my phone) and, to be honest, I prefer to just keep a food journal as a Word file on my computer. It's just easier than wasting time finding something similar to what you ate, and I have a pretty good sense of how many calories are in things. All I track are the calories--like you, I'm not interested in tracking carbs & things, although I do try to eat healthyish. The plus side is that I try to overestimate calories when I'm not sure, so I probably end up eating less than I would with one of those apps.
In search of a lost signature...