This upgrade has made my iMac unbelievably fast. So, it's definitely worth it.
However, the install itself is definitely not for the faint of heart. It took me a solid 3 hours. The connectors are tough to disconnect. (I found it easier to use the clamps than the spudger, but worried about squishing the plastic.)
The OWC video is great. I used it in conjunction with the iFixit manual and found them complementary. I liked laying the machine flat a la iFixit, but many of the steps, like keeping the airport card connected, were better from the OWC.
The screw driver kit is cheap, but gets the job done.
So, in closing, I'm not sure how you can evaluate whether you can do this. I've poked around computers for a while, including a 2007 iMac and this was definitely harder. That being said, the instructions online are clear and true to form. Plus, I have an unbelievable sense of satisfaction!