I thought the grey was easier to read than anything. Maybe it's all in the kind of screen you have.
I have a full time job and a per diem job that likes to call me at all hours of the day and night. And I use my cell phone as my alarm clock, so I was getting woken up all the time but usually either an hour after I fell asleep or an hour before I was supposed to get up and go to my other job. In my confusion, I'd often hang up on the supervisor who was calling me, thinking it was my alarm.
But I just recently figured out there's a button on the side of my phone that allows me to set my phone to "alarm only!" It doesn't make any noise when I get a call, text, or voicemail, but the sound still works for the alarm. Best thing ever.