All modern browsers support SNI [1]. I guess if you need to support IE8 on WinXP you'll have problems. And IIRC, wget on Ubuntu 12.04 doesn't support it (while curl does). But it's picked up a lot in recent years, which thankfully eases the dedicated IP requirement in many cases.
Absolutely no need for a dedicated IP unless you want to support very old versions of Windows or very old versions of Android. I haven't allocated a dedicated IP solely for SSL in years.
