Very good... you were able to achieve an "eye catching" design that the bottle needs, that many other entries, though well done, didn't seem to include. This is something you can pick off a shelf from a plethora of other options rather than melt into the background.
As a picture I prefer this one, but on a water bottle, the day one would work better; simply because the Day picture looks more like glacier water. This one has great contrast, but might seem too busy on a water bottle. Love it though
I personally quite like this one, btw congrats on the front page feature
But anyway, I like this version because the dark background helps to highlight the bird, and it's the first thing you tend to look at that way, I found that in the day version I briefly glanced at the background before the bird. Contrasting can be important when you want to highlight a specific part, although of course it's mainly about the actual bird itself, but the background can help towards showing off the bird, either way, great work!
I prefer this version. The dark night contrasts the bird very well. However, for a bottle of water, the daytime version would be better because water is supposed to be clear like the pure white sunlight etc. etc. >>;
I prefer this one over the Day version mainly because the Day version seems too bright. The cool and warm colors match perfectly and give it a sort of peaceful atmosphere to it. In the Day version, the white background throws it all off and looks like a pheonix doesn't fit in; or shouldn't be that choice of mythic being. If it was a celestial dragon (eastern dragon basically) in the Day version, then the white would fit.
......That's the Graphic Design part of me speaking. Sorry if this offends you or anything, but I'm just giving my two cents.
I like this one better. The dark contrast makes the bottle an attention grabber. But if you're going to use the white one, I think it'd be cool if you can make the white parts transparent. Just an idea.
Night is much better. The white background was too empty. If it had been a very light blue with white clouds, then there could be a better idea of background, but with only white space and barely visible petals, it was kind of lacking. The dark background with a glowing moon is beautiful without distracting from the subject.