No phone has a camera good enough to be described as a 'serious' camera by anyone who knows about proper cameras.
Camera phones have lenses of only a couple millimeters in diameter.
How much light can get through that? In low light exposures are long, leading to blurred pictures, or the sensor is running at a very high ISO rating leading to excessive noise.
Image stabilisation stops camera shake but it cannot stop subject movement.
A camera might have a 10Mb sensor but that doesn't mean the lens is that good.
The resolution of a lens is limited by it's diameter. The image of a point produced by a lens is a disc, not a point. The diameter of the disc, called the Airey Disc, decreases as the lens diameter increases, so big lenses have better resolution than small ones of the same quality of manufacture.
Resolution in radians = 1.22 Lamda / D
Where Lamba = wavelength of the light and D = diameter of the lens
Optics that perform to the limits imposed by their size are called 'diffraction limited' which is as good as you can get for a particular diameter of lens or the mirror of a reflecting telescope like the Hubble Telescope.
Scroll down to...Resolution
http://www.astunit.com/tutorials/telescope.htm . . . . .
Scroll down to ...Diffraction limits the resolution of the system.
On the way, the sugar-loaf graph you see is a picture of the Airey Disc. Notice the figure underneath
http://www.luminous-landscape.com/tutorials/resolution.shtml . . . . .
http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm . . .
The same formula applies to telescopes for both lenses and mirrors which is why such big telescopes are made...more light collecting area and better resolution.
More paragraphs could go on the exposure systems of cameras but one arrow through the heart is enough to kill.
Phone cameras are no rivals to even simple low cost point and shoot cameras.
EDIT
You make a good point about having it to hand. That's true of any camera.
The cameras of any use are the ones you can use. If you ain't got it with ya, you don't get a piccie.
Speed and ease of use can also determine whether you get a picture or miss it.
I always carry a camera. It's just as quick...quicker most times in actually getting a picture...to get a camera from my top pocket as to get a phone from it.
With simple film cameras like my old Ilford Sportsman (winner of several photo comps for me ) there's no start-up time. Digitals are a bit slower to use but are handy to have. I use an old Minolta and a Coolpix but other brands are just the same. Brands don't matter for everyday cameras.
Phones can be even slower to use than digital cameras.
My phone is a phone for me, nothing else, a Samsung Extreme. I get out walking and cycling in the hills quite often. It rains a lot here. Waterproof phones are really handy for us.
. Phone and digital camera fit into one pocket most times. Film camera goes in another pocket.
No probs. Good comms and good pics.