advantages and disadvantages of playing white

The biggest advantage of playing white is you're not playing black.

At your level their are no "disadvantages or "advantages" to playing white, or black.

"... White, having the first move, has the initiative. The initiative means time and action, and is therefore an advantage. …" - Capablanca's Primer of Chess

At the top levels, White certainly has an advantage, as evidenced by the fact that White wins more often than Black. At my poor patzer level (1700 USCF), Black probably does just as well because we can steer the game into channels that we might be more familiar with than our equally patzer-like opponents. Thus, whether White opens with 1. e4 or 1. d4, we get to choose a defense that we know pretty well, while White will only know a little bit about each of our possible defenses.

There are no excuses. If you want to win a tourney, you need a high score. Period.

At U1200 black seems to have the advantage. White commits mistakes first like hanging a piece, unsound attack, overextending pawns.

White has the initiative, but what that initiative truly amounts to is that white is able to force a draw... it's not a winning advantage, so the stage is still pretty equal.

As for any downsides to playing white, the post above mine says it all - first move privilege comes with it's own pressure.

On a more practical level, I think it all depends on our training; different sides of the board require slightly differing strategies. The question then becomes, what strategies are you mostly invested in generally?

But what does that have to do with the ups/downs of each side? Contestants, and the games they play, represent their training to a large degree. It's a packet of mixed veggies and you've got to take the carrots with the peas. 

"... At the beginning of the game opponents have the same conditions, their exactly equal forces occupy equal territory and are arranged symmetrically. Yet White still has an advantage. This advantage is the right of the first move. How large is this advantage? Statistics show that in games between masters White usually wins more often than Black: approximately 60 to 40. It is more difficult as Black. In games between novice chess players, color is not the most important factor, ..." - Journey to the Chess Kingdom by Yuri Averbakh and Mikhail Beilin