I haven't been playing as much as I would like to this past week. I've been pretty sick and my brain just couldn't cut it. I took a pretty big loss dive when I did try to play. (I believe I lost about 10 games almost consecutively.)
I'm just barely hanging past 1100, however I'm ranked pretty high among random users which I think is great.
My new goal is to reach 1400+ by my birthday (December 9th). I'm sure this is very reasonable. We'll see if I can do it though.
Zerg
Although Zerg feels underpowered even with the new Zerg favoured patch. I still very much enjoy playing them. Terran is a very close 2nd though, with Protoss being far behind. Not that I don't like Protoss, I just can't PvZ for the life of me.
I like the Zerg play style mainly and how it's more macro focused. I like their harassment capabilities without risking an "all-in", and their easy tech switching methods. It really throws your opponent off when you suddenly start producing different units. Zerg is easily the best race for doing so since all you need is a single tech building. Unlike Terran or Protoss where you have to make multiple buildings all at once, which is quite slow and risky.
Taking over the map by spreading creep all over just looks cool too.
This is more of a ZvT/P build I enjoy using. It doesn't work so well against another Zerg because of Banelings.
Muta/Ling
10 Overlord
14 Hatch (At Natural Expansion. This depends on the map though.)
14 Pool
14 Extractor
16 Extractor
18 Queen (Once your 2nd hatchery finishes. It gives you two supply for your queen.)
Lair once you have collected around 200 gas, and make sure to throw down your spire as soon as it finishes. It's also important to try to not let your opponent scout your spire tech. mutalisks are easily countered so sometimes suddenly going hydras instead might be the better choice.
Depending on the pressure my opponent tries to play, I will make a few zerglings and Spine Crawlers. 4 is usually the magic number, it can take out quite a large attack force. When you have zerglings as well you can fight off almost any attack unless they do an all-in build then you might need to add more crawlers, and more zerglings. Scouting is very important at this stage in the game, so you can compensate your defenses for his unit count.
Once you get a small amount of mutas like 6-8 I'd recommend you go and harass your opponent as much as you can. Ideally you'll want to focus on disrupting his economy. Adding in a few more mutas while the gas comes in. Don't fear stalkers, mutalisks eat them for breakfast.
It's also very important to expand again in a secret location while your opponent is busy defending himself. You should also be teching and making different units. I usually like to go with zerglings/banelings/infestors. Against a Terran he'll start making more marines or thors to compensate for your mutalisks. This leaves him extremely weak to zerglings/banelings. Same thing can be said about Protoss, he'll most likely make cannons and more stalkers. Leaving himself weak to zerglings.
If the game drags on you should have enough bases and income to support Ultralisks. They're really solid units and a lot of bad players really over look them. A few ultralisks easily turn the tide in a battle.
I absolutely love mutalisks. I really liked them in BW as well. Hydralisks were my favourite though due to the fact they were so bad ass; their sounds, looks, and attack. They lost all of it in Sc2.
Mutalisks are such great harassment units. With just a small number of them I can keep my opponent in disarray for a very long time. They're very mobile and can grant you easy early-mid game map control in most cases. If you plan on playing Zerg I would really recommend working towards having great mutalisk control.
Here is a good video which shows the effectiveness of mutalisks.
Credit to: TheUENtv @ Youtube.
In closing I still enjoy using all the races. I still plan to stay a random user. Maybe I'll finally pick a race in the coming months. We'll see though.
I also plan to write up more strategies for Terran and Protoss.