my own experience? I've been developing for the web for 19 years. I know the issues with UA strings. It's an old argument. On the modern web, for the most part

my own experience? I've been developing for the web for 19 years. I know the issues with UA strings. It's an old argument. On the modern web, for the most part UA sniffing isn't necessary. If you do need it, there are plenty of libraries that will very reliably sniff strings which account for 99.99% of the web. Possibly mobile strings are an issue, but there are services like http://wurfl.sourceforge.net/ http://wurfl.sourceforge.net/ which will again get you to your 99%+ range. Of course do all the other things like feature detection, graceful degradation and progressive enhancement, but I find the entire argument a bit overblown.