Ok, if all you want out of your camera is for it to take nice pictures on a vacation, be less than 600 USD and be portble, your best bet is a high quality compact camera like the rx100 (note there are 3 successors to it for more money of course):
http://www.amazon.com/Sony-DSC-RX100-Sensor-Digital-Camera/dp/B00889ST2G
Will a point and shoot take good quality pictures? Yes. Point and shoots will fall behind DSLRs image quality in 2 situations: low light and printing large images. If you want to shoot in the dark or print poster sized images, you will need to look elsewhere (and probably spend a lot more than $600). However, since you say a smart phone takes nice enough pictures, you will probably enjoy the better image quality of a nice point and shoot, but not miss the ability to print posters.
Do point and shoots fit your budget? yes, I picked one of the most expensive ones as an example. A S100 is even cheaper and still a great camera.
Are point and shoots portable? Yes. They can often fit in your pocket without discomfort (depending on your pocket size of course). That is more than I can say about a M43 camera. They are smaller than a DSLR, but not so small you can carryone around easily without a bag.
Based on what I have read from you, I would bet a point and shoot would serve your needs better than a M43 camera. However, if you intend on making photography into a serious hobby (i.e. willing to poor more money into it over time for better lenses and bodies) and want to take pictures beyond vacation photos, then a M43 camera might be for you.
What you have to understand is that M43 cameras and DSLRs are meant to be paired with expensive lenses. Buying a DSLR or M43 camera and not buying nice lenses is a bit like building a nice house on a shitty foundation. In a few years your nice house will start to crumble and while you spend all your money keeping it standing your neighbohr who spent more on his foundation can spend his money on a new pool.
So, ask yourself what you want out of the camera. Do you just want it to take better pictures than an iPhone? Get a point and shoot. Do you want to make photography into a serious hobby? Get a M43 camera and some starting lenses.
Here are some good starting lenses:
http://thewirecutter.com/reviews/the-first-micro-four-third-lenses-you-should-buy/
Can you see yourself buying 2-3 of those lenses in the next year?