I just read, not so new news that Opera will be switching from their own engine to webkit to save development costs and contribute to chromium project.
I found the news on Opera dev news
it looks like finally rendering problems for Opera will fade away.
They also say that they will contribute to webkit and chromium projects
The Switch will be at the need of this month for mobile browser
Isn't it Good NewsConsumers will initially notice better site compatibilty, especially with mobile-facing sites - many of which have only been tested in WebKit browsers. The first product will be for Smartphones, which we'll demonstrate at Mobile World Congress in Barcelona at the end of the month. Opera Desktop and other products will transition later.
Opera Developer Home Page