i guess your original mini has the same processor speed and 2x's wifi speed built into it. Im sorry but i notice a huge difference. No choppiness with ios7. If you don't notice it now just wait till ios8. The original mini was built with 2 year old technology(a5). At least it was close to 2 years old. it will be dated as they update the software.
its like going from an iPad 2 to a rmini... or air...
I get the specs and I even stated that the processor was faster...benchmarks blow it away. But I haven't seen it in usage while browsing or using any of the apps I use all the time. Again, I don't game so I'm sure there is a huge difference.
When iOS 8 comes out and a more powerful rMini, I'll likely upgrade then (probably wouldn't put iOS8 on this 1st gen Mini). Only sooner if I find a really really good deal on one.