I use modernizr on most of the scratch site builds and this will be used right along with it going forwards…
Conditionizr – Perfect Supplement To Modernizr
First things first – Conditionizr does not intend to replace Modernizr, nor would it be able to. Instead is has been developed as the perfect supplement, so that both solutions work best when used cooperatively. Conditionizr is based on the same classes approach Modernizr is, thus making integration seamless.
Instead of adding the conditions to the markup, Conditionizr works completely markup-free. All you have to do is call the script right after jQuery and Modernizr (if you want to take advantage of that) and add a configuration part to the head of your document. All supported browsers can be configured to how far the influence of Conditionizr shall go. You can choose to en- or disable the use of specific classes, styles and scripts separately. In the same way you can define whether Conditionizr shall take care of OS and retina detection.