I'm really excited for this one, hopefully not overly excited... I have great memories of SF II and I have high expectations for the live port of it. Anyways, I really like how well rounded Xbox live has been shaping out to be. Cloning Clyde is entertaining and it's one of the many XBLA games that has mass appeal -- it's girlfriend and niece/nephew appropriate.
IGN is running a great article on innovation with XBLA titles and, even though they mostly talk about Lumines Live, I found it interesting because it briefly touches on some development challenges and the future of XBLA. Check it out.