I haven't used T3 yet, was previously planning on using YooTheme's UIKit / Warp framework for my projects going forward, but was disappointed to find out they're not even partially supporting IE8.

Bootstrap 3 has pretty good support for IE8 with minor tweaks, and I was about to start my own Joomla starter theme / mini-framework based on Bootstrap when I came across T3 Framework (better late than never, I guess)

I can't wait to see the T3 implementation of Bootstrap 3, really looking forward to it.