opera completely not compatible with my site (Template, css, some jQuery plugin and etc..) i tested in firefox, chrome, even IE, but only have a many problem with Opera. problems are very bad, for eg. when i opened the site with opera, after a little scroll down, template disappeared, just background left! or not support some css3 and jquery.
i tried to compatible my site with opera but it didn’t.. so i decided to block opera and redirect users to a page with a message.
If you want my opinion, blaming your users (blocking Opera is blaming users) because your site is badly developed (having a compatibility problem with a rendering engine is bad development) is kind of inappropriate.