This is a fantastic site to upload your work and get reviews. If you are active in the community you will get plenty of reviews and thoroughly enjoy your experience.
There is more to WdC than just uploading and reviewing writing. There are loads of official (managed by staff) and unofficial (managed by members) contests. I have ran many in my 5 years with the site and have entered a fair few, too.
The best part of the site in the community. Via the newsfeed, IM, email, and forums I have got to know some brilliant people over the years. Of course there are some members who aren't very helpful and some who are simply not nice. In these instances, the site has easy to use member blocking tools so you won't be bothered by them and can continue enjoying the site. I've only had to use this feature once or twice.
With an upgraded membership you can create your own groups (you can join groups with a free membership). Groups are a great way of bringing like-mided writers together. I run one of the larger fantasy/sci-fi groups on the site and have great fun creating contests and activities.
It is my activity on the site that led to me becoming a Preferred Author (or Yellow Case). It is not because I have spent loads of money on the site. In fact, since joining I've spent most of my time with an upgraded membership that I haven't had to spend a penny on. I've maintained my membership through earning gift points (the site's virtual currency) by being active in the community. And in a couple of instances members have outright purchased my membership for me. I've also purchased their merchandise as contest prizes using only Gift Points. If they only awarded preferred author status to those who spend a lot of real money, I wouldn't have got it!
Some people have commented that coloured cases win more official contests and that those who are 'just' registered authors never win. This is not true. The last official contest was won by a registered author as was the last review contest. In fact the official August contest had only registered authors place in first, second and third.
The reason it can seem like more preferred authors and moderators win things is that they are generally more active (that's why they get the coloured case) and enter more contests.
The people who run the site are amazing. There is a forum dedicated to member suggestions, and sometimes they are implemented. They have always been quick to respond to me when I've asked for help.
Ultimately, if you just upload your writing and expect to get reviews, you will be disappointed. The more you put into the site (in terms of time and effort, not money), the more you will get out of it.
I have not been paid or rewarded in any way for this review, I just wanted to let everyone know how awesome the site is!