Does anyone use a sunrise/daylight alarm clock for those early morning runs?

I've recently discovered that I love early morning runs. So far, I've been waking up naturally with the morning sunlight (event though I wear a very fetching inflight eye shade so I don't wake up at a really stupid o'clock), and heading out of the door with no problems. I haven't yet set an alarm to wake me up for a run. I really want to keep the running habit going during winter and the dark mornings. I've read a bit about about sunrise/daylight clocks, and how waking up to one of these feels so much better than being suddenly woken by an alarm. Does anyone use one of these clocks? What are they like? 

i wake up with the daylight, which sometimes is too early, sometimes just right, depending, you know, on how i feel upon waking.

i am considering one of those sunrise clocks, cos winter mornings can be so brutal! but they're expensive . .

but i'm lucky in that i wake up with the click of the alarm BEFORE the alarm goes off, so have time to prepare for the radio coming on!

Cambrige: Join us on 'Who gets up to run at  Stupid O Clock' Thread. The Early moning runners thread

You'd be made most welcome.