The absolute best tool i have found for scraping is Visual Web Ripper.
It is not open source, and runs in windows only, but it is one of the easiest to use tools that i have found. I can set up scrapes entirely visually, and it handles complex cases like infinite scroll pages, highly javascript dependent pages and the like. I really wish there were an open source solution that was as good as this one.
I use it with one of my clients professionally. Their support is VERY good btw.