On the other forum in the audio section there has been a lot of discussion about this. Those guys try out and test more audio equipment than you can imagine. The overall top 2 comes down to the Pioneer 6900pros and the DD. No need to look any further than those 2.
What are your goals for those speakers, your system? Budget? Answer those questions and you get your choice.
I went with the 6900. At the time it was what was recommended to me. I have a bridged ss pn4. 1000d powering them. They get plenty of power and they get loud as hell. Im totally satisfied with them for now. The DD 6x9 are supposed to be even better.
Either way they are your #1 and #2 choices.
2009 Road Glide. 16 in Vindikta Wild Cats. Aquatic AV, Stinger 700X4 to MMatts, Audiopipe horns.
Ground Zero 7X10 in the lids w/ sspn.4 1000d, tuned with DD Audio DSI-2. S&S 106, lifters, push rods and AC. Drago 2. CycleRama 575. Progressive monotones -1in. 12in. HD adjustable rear shocks. Painted inner fairing. Tuned with TTS. Blacked out!