i don't see how the 3e is a better mechanical filter than the 3. It's turn over is less, has a smaller filter volume and pre filter (8.6 litres compared to 13.5 litres on the 3). Also the 3 has 2 inlet pipes compared to just the 1 i believe on the 3e. Stick 1 inlet at each corner of the tank, and already you got an advantage in getting to dead corners than the 3e.
When it comes down to it, all a cannister filter is is a pump in a sealed tub. The 3 will cycle more water through it per an hour than the 3e and filter the water through more media. If you got bio filtration covered with another filter, you can add more floss in the 3 to really sieve the water.