I think its fair to say quicksilver is more powerful, you can really do almost anything in it. I however didn't use many of the power features (resizing images

I think its fair to say quicksilver is more powerful, you can really do almost anything in it. I however didn't use many of the power features (resizing images or composing e-mails). Alfred is really just a launcher with a few nice bonus features (clipboard history & spell are my favourite) where as quicksilver is more like a command line power house.