Hello, Binh!
The MediaFire file hosting is much better than the popular ones
(like Rapidshare, Megaupload, etc.) I have a free account.
My files have 200MB size restriction, and an unlimited time of storage!
Why I would continue to store these files on MediaFire :
1) I have a good 2.5 Mb/s download speed, but a small 0.5 Mb/s upload speed,
so it would take a Lot of time to upload them to another place.
2) Sometimes these files need an update
(e.g. new application which I must include to the archive)
If I will do the updates by myself, it would save some of your time,
and they will be coming out a bit faster.
3) It will save a Lot of your money
(my files already have more than 90GB of served bandwidth

)
And there's no waiting time or any limits for downloaders (except some ads)