When I first started, I saw slight gains after 3 months, but after 8 months I was noticably stronger and more muscular. Lots of body fat started to melt away after 6 months, making me more cut even though I wasn't really dieting for that effect. Now that I am cutting I have noticed slight decrease in size but very nice definition. I'm pretty strict with my diet, though.
I think you should see noticable gains after 6 months, esp. if you are lifting heavy. Just MHO.