I switched years ago, initially quality for non-US-centric results was lackluster, but it is excellent now. Considering that I'm stubbornly trying to use Tor wherever possible, the fact that it isn't blocked or hampered (like Google does with its crappy twisty little maze of captchas sometimes), is an additional advantage. I honestly cannot remember when I last felt I had to use "!g" and was proven right by better results. Perhaps Google Image Search is still worthwhile.