Kenwood 9990 or Alpine 910?
 

I really wanted to wait for the Alpine 928, but with no release date in sight, I will have to settle for one of these two. Which is the best option for sound and screen quality? Nav is not a huge issue.

The 928 should be out in a few months, I can not imagine it being the fall especially with a pre order available. I would wait for that or if you can not wait get the 9990. I only went with the 910 because of the speed of the interface.

Are the 9990 and 910 similar in terms of interface speed?

Pretty close, boot up time goes to the 910.