I've been a very sound sleeper all my life. Likewise, all my life, I've been in search of an alarm clock guaranteed to wake me up. No sound-based clock could ever be counted on because I could (and frequently did) get up, walk across the room, silence whatever was blaring, ringing, or buzzing, and get back into bed and go back to sleep and never know I'd done it till I woke up having seriously overslept. I'm also a night person who, for much of my life, has had to live on day people's schedules. It's a bad combination.
Sound familiar? If so, this clock may be the answer for you as it was for me. I love this clock. (Note: Mine doesn't have the white noise generator so I can't comment on that; otherwise, it's identical to this model.)
The light gets brighter in a way much like the sun brightens the morning sky - consistently, over a set time span. The light it produces is very natural, very "sun-like". Experiment with where in the room it's best for you. I have it on the bedside table, not quite where it shines right into my face but close enough for it to register, as if I had an eastern-facing window right by the bed and there was never a cloud in the sky at sunrise...and sunrise is whenever I need it to be.
You can also set it to begin beeping, but I seldom need that; if you like a snooze-alarm, it has that too. Once it starts beeping, you can hit a button to turn the light down and a few minutes later it'll get brighter again. Nice.
The reliability has been great. I'm on my second one of these, having gotten one of the disc ones first, from a Sharper Image catalogue in the mid-1990s. It finally played out after about 8 years, and I replaced it with this model from Bio-Brite which I liked better only for cosmetic reasons, not because of any dissatisfaction with the first one's performance.
I truly depend on it, and when I moved 1200 miles in the late 1990s, this was one of the things that came with me in the car, instead of going on the moving van.
My only regret is that I didn't find it sooner in my working life, especially when I was working rotating shifts. Ugh. Now that I've had a job with "normal" (ha) hours for a few years, I still don't enjoy getting up at what feels like a wrong time for me, but I can and DO get up when I have to and it's not the miserable experience it used to be.
I STRONGLY recommend this product for anyone who has a hard time waking up to a noise alarm OR who would just rather not be jangled out of sleep OR who has to wake up at some time other than natural dawn OR has to get up at a time other than when their own internal clock would have them wake up...or all of those, like me. Yes, it costs more than a battery-operated clock from a discount store, but it does what it says it will do.