I've been using Opera web browsers on mobile devices for many years now, starting with Opera Mini on early smartphones to Opera mobiles on my more recent devices that have enough processing power to quickly render full web pages without the need for compression. Apart from nice to have features such as the speed dial with icons of web pages the main feature I like the Opera mobile web browser for is zooming into web pages with text being reformatted to the screen width no matter what the zoom level is. As text on many web pages is too small on the small sub 4 inch screens I prefer, this reflow mechanism is a must for me. So when I heard that Opera has changed the underlying rendering engine I was a bit afraid that the text reflow mechanism might have disappeared in the process.
Fortunately it hasn't but it has to be activated in the settings after upgrading to the latest version. My web pages on the speed dial screen are also still there and I have the impression that pages are rendered a bit faster than before. Going back to the previous page, however, seems to be a bit slower. Both observations are very subjective though and I could easily be wrong on both accounts.
The new design looks very fresh and appealing which I consider a high praise from someone who more often than not likes the old design more than a supposedly new and better one. The tabs functionality was also much improved over previous versions where I always had trouble closing tabs I no longer needed without accidentally switching to them instead of closing them. Tabs are now shown as cards when clicking on the tabs icon so it's easier to close them. Also, Opera has changed the way pages scroll up- and down. The scrolling is no longer soft and continuous but the pages drag to a halt pretty quickly. All very smooth and I have the feeling the pages stop scrolling closer to where I wanted them to stop than before.
From an ecosystem diversity point of view I would have preferred Opera sticking with their own rendering engine. From an end-to-end point of view, however, the browser has gone a good step forward with this new version. Kudos to Opera for a good update!