For quick touchups, I honestly feel that picasa outshines lightroom by huge bounds for it's easy to use interface. Rather than spending 3-5 minutes on each photo, i can do it in less than 30 seconds. In lightroom, you do get more control over colors and finer details, but when it comes to speed and time spent sitting away on a computer.... picasa wins.
i do have lightroom but i just feel like it's a chore to use. when i find a picture that i really want to keep as a keeper, i will turn to lightroom. other than that, it kind of sits on my hard drive, neglected.