I used to know a pro photographer who always swore by Photoshop and then when Lightroom came out he said that for a photographer it was much more intuitive to use if you only wanted to do basic tweaks, levels, crop, red-eye etc. Well I think it's come a long way since the original version - I use it as a tool of preference but if I need to do anything in layers, although you can do it in Lightroom, I switch to Photoshop.
You pays your money and you takes your chance!