Opera Software is acquired by a group of Chinese companies,[1] and one of them is Qihoo 360, which has a lot of negative history.[2]

1. https://en.wikipedia.org/wiki/Opera_Software

2. https://en.wikipedia.org/wiki/Qihoo_360#Controversies

Opera uses Chromium under the hood. Have you used Firefox lately? Personally I don't think there's anything clunky about it.