i-Dots have a thinner front sight post and do not have the "proglo" colored "ring" around the tritium.
The i-Dot pros have the proglo front sight and is a little wider to accommodate the colored "ring".
Rear notch is the same on rear sights (ie they are the same. The only difference is the front sight).
There is still plenty of light using a proglo front sight and i-Dot rear.