All depends on your individual and unique personality and playstyle

There will be players that will say things like:
- Protoss is OP
- Protoss is easiest race
- Protoss requires least amount of APM to win the GSL.
- Terran's Widow mine requires no APM.
- MULE is OP.
- Zerg is the hardest race to play.
- Terran is the hardest race to play.

well, all these claims are ridiculous. Meaning if you are the type to play super aggressive early on, you will find zerg and terran quite compatible.

(I myself am a Random Player), I use all races to the maximum extent I can possibly play. Each race has their own unique perks, advantages, and disadvantages. I will try to make this post brief as possible.

First of, No race is either the Easiest nor the Hardest. No race is more overpowering than others. These claims were created by trollers, provokers, try-hards, sore losers, and ignorant players.

Play each race, as best of your abilities will allow. Figure out each race's strengths and weaknesses. Assess each builds to the maximum extend possible. You will end up diagnosing all races capabilities. You will find out that all races are equivalent to each other, until you download/update sc2. Sometimes, updates may and can ruins the balance issue. But balance, itself is unbalanced. Sometimes you will need to find a way to overcome an obstacle around imbalanced metagaming. That is when a new "Gosu" appears, when a player makes a breakthrough metaplay surpassing an invincible thought strategy. Similar to when Stephano created the 200max roach build, but was countered by a Gosu player named, Parting with a sentry/immortal counter, which annahilated the 200max roach build. Or when 4 gate was first introduced, no one was able to counter it correctly, until another player created the 2 gate robo build which countered it.

lately, blizzard has been creating updates to tweak units, unit movement, terrain changes, abilities nerfs/buffs. And it has withheld Gosus from ever emerging. You can become the next Gosu, if you find a way to break the impossible, and it has repetitive results. 

The Reason why I chose Random, first it creates more pressure for the enemy to scout first. Because enemy acknowledge creates the type of build to progress. As Tsun Tzu says, "Know your enemy, know yourself, and you will become the victory after a hundred battles." I take this quote to heart, so should you. You must have maximum game mechanics and versatility. (Tsun Tzu, was an ancient chinese philosopher that created "The Art of War," you will find these words familiar to you, as we all use it today. He was like the movie 300, but lived after the fight.) Second, I am indecisive when it comes to choosing, terrible ADD decision making, so I let the game, itself, do it for me. at this stage, I know what the enemy race is, he does not. I just need to know where he is, and what hes doing. He cannot expand easily, because i may be a race that just might attack while he's expanding. Timing is also thrown off.
Sure playing random is difficult, since you can't just master one race, but it totally kills off the boredom of one race. Dont 100% take and comply what others tell you to do. That is your decision. This makes everyone unique. If you copycat someone else, it is super easy to defeat you, since they can predict what the original player does and acts. If you copycat Idra, we all know he just macros the hell out, so we can just cannon rush basically... easy peasy. But if you played variations of Idra, with mind games, and new forms of metagaming. You have become a new, yet unknown Master of a gamer. Pro players do not copy other Pro player's style. They choose their own, and that is what makes them a Pro player. Excluding "standard play" which is a neutral form of play, keeping the enemy in guessing state.

You hear this all the time, Good Luck, and remember, HAVE FUN!