And also had single process model which failed completely when you had 50 tabs and Youtube etc. implemented in Flash. Main tab use case being unusable around the time Chrome came out was what motivated me to switch. Also, extensions getting broken at each update.

Yes, the multi-process model was a godsend. Especially since it was around the time multicore processors started becoming more common, especially on laptops. Perfect timing. Terrible javascript not locking up the whole browser was fantastic.