Couple of things;
- It has better signal to noise ratio being an external unit, I find the AE5 has a very very slight background hiss at high volumes and quiet sound effects, the G6 doesn't. Normal volumes though you probably wouldn't notice.
- G6 has an external control unit, finer volume control and much more convenient changing to different headphones.
- AE5 only supports stereo over optical out, G6 does 5.1 dolby digital
- G6 has optical in supporting 5.1 dolby digital
Negatives
- No LED strip support
- No 5.1 analog out
Apart from the above they are pretty much identical in features & control, in my opinion the G6 is the more flexible unit being external and works with more than just PC's (eg consoles and home theater setups, even phones although it will cane your battery).