Problems: Fan in my computer (mac book pro 15 inch, A1260 model. AKA the model that's a nightmare for hard disk upgrades) made it sound like it had a motorcycle inside. My hard drive was just too small.
It went really really well. I followed the instructions. It really helps to print them out. Every screw I pulled, I taped to the picture on the paper where it was supposed to go, this really helped me move with speed and save myself the hassle of missing or leftover screws.
A quick warning on the Torx screws on the hard drive. Make sure you use a good torx screwdriver, the screws are tight enough that they will damage the screwdriver tip otherwise. Mine still works, but it is all twisted now. :/
Definitely watch the video. It helps a lot getting a sense of how to pull the parts out and how much resistance to expect.
Oh and be careful with the tape.
Definitely watch the vid. They really make you aware of how exactly to pull parts and deal with ribbon cabling or connectors.
To the iFixit guys:
The instructions are awesome. Clear, concise and to the point. Every single step. The videos complement the manuals like a dream. Details on practical advice such as using a credit card for lifting glued ribbon cable to prevent damage are incredibly useful. First deep repair I've ever done. 100% success thanks to the iFixit guys!