OPERA VS FIREFOX: WHICH ONE IS BETTER

Which web browser is the best Opera or FireFox?
What do you think?
First imagine web surfing without Opera & Firefox.Both of the browsers are good in their own case.

The best advantage of Opera is probably the fastest browser.I've tried both but Opera seems better for my dial up connection.After trying all tweaks for firefox nit result is zero.

But opera is not protected from hack.You can easily hack it.Here is the main advantage of firefox the most secured browser.

Tabbed browsing is available for both so no comparison.