False dichotomy... Either use a broken mobile site with half the content, or a full site that barely loads.
No, I'm saying that the 'features' on the full site are rarely worth the time and bandwidth required to load them. I'm not complaining about things like Google Earth or other high-bandwidth services, but the amount of visually and functionally useless cruft on many sites, news sites in particular.
You don't want to use full site because it has too many features and have, therefore, too big size.
You also don't want to use mobile site because it doesn't have all the bells and whistles.
Chose one :) ... or use Opera Mini and/or ziproxy on your server