I have six of the original bells and love them. The minimalist design is what sold me, then when I received them I liked the sound. Can't comment on the compact.
The difference between the original and the compact besides the obvious is that one the original is made in USA and the compact is made in Taiwan. Some people care about this, as a Canadian I don't. If it matters to you then you might have your decision.
In my province it is law that every bicycle has a bell, rarely enforced but if you do get pulled over you can get a ticket if you don't have one. Even if I never use it, I at least need it to be compliant with the law. Of course every jurisdiction has it's own laws. If have to buy a bell, then Spur Cycle is a good choice and not the Rock Brothers who ripped off the design and sold it cheaper.