I work for a Fortune 200 company and I just recently led the effort for them to adopt Chrome Frame. We were using a charting package that we could either render in Flash or SVG and because of our BYOD strategy we chose SVG but the performance in IE8 was abysmal.
Chrome Frame fit the bill nicely. You include a tag in your HTTP header to request Chrome Frame. If it hasn't been installed then IE8 renders the page. The nice thing is the site self-selects that it wants Chrome Frame so your legacy sites continue to get IE8. Even better, your users are still launching IE so you don't have the support hassle of this site requires this browser while this other site requires this other browser.
Meanwhile this gives us an opportunity to modernize our legacy web applications. Chrome Frame has been a great solution for us.