I would say somewhere in the middle but closer to the uncontrasted picture.
High Contrast is naturally a good thing in most images... but in your contrasted picture, you are starting to lose detail at both ends of the exposure. Your background loses detail and turns in to what we call crushed blacks. If you don't care about seeing the background then this is fine! In the contrasted picture, some sensor noise is also made more visible in your darkened hair which is also starting to merge in to the shadows as your hair is now slightly too dark on top.
What is more serious is that you are losing highlight detail on your face. In the second picture, your nose and cheek are starting to clip and turn in to areas of pure white that we call 'hot spots'. This is a type of overexposure that is particularly troublesome with the narrow(er) dymanic range of digital cameras. It is generally considered a very bad thing unless that is the look you are going for. For example, this effect was used on the cover of one of natasha beddingfield's album covers to almost obliterate her face leaving eyes and nostrils. For normal portrait photography we wouldn't push the contrast this far. Most would agree that it is 'over-cooked'.
Try again and add a little bit of contrast but not as much as you did. Alternatively, mask out your face and apply contrast to the background and your hair. Either apply a minor increase of contrast or leave your face how it is. This would look good in my opinion.
If you have software that can do curves and you know how, you should try to push the contrast in the lower half. Assuming that you're using a curves mod similar to Adobe Photoshop I would put a handle bang in the middle to hold the midtones in place and another handle 3/4 up to hold the highlights in place and prevent blown highlights. Then I would put a grip about 1/4 up from the bottom and pull this down slightly to increase the shadow contrast but leave everything else as it is. Curves will always yield better results than any sort of 'contrast slider'. Contrast is a more complicated thing than can be done with one variable. This would be a more professional way to make this photo 'pop'!
Good luck!
