buy a frame or whole new bike?
 

I have an 89 trek 2300 right now and want to upgrade in the next few months. I test rode a Bianchi Eros and liked the frame, but the shifters felt really crappy, but the steel frame felt plush and smooth. A friend heard my complaints and said, why not just buy the frame you like and all the components you want also? Does anyone know if that route is just more expensive or does the customizability pay off more in the end? Also it seems that all of the big manufacturers-bianchi, trek etc. only sell really expensive frames as a set. I probably wont spend more than $700 on a frame. Any ideas?