Hi,
I believe that some of your problems with Apple Quick Time can be solved by downloading and installing the free "Perian" software this provides Quick Time with native support for a broader range of additional media files and formats and it also installs a broad range of Codecs not provided with Quick Time, thus providing it with improved playback of various media types.
It is 100% free and can be downloaded from
http://www.perian.org and many other reputable websites.
I also like the VLC Media Player and like yourself use it quite a lot as it can handle most media formats and is easy to use.
Another great 100% free Media Player I really love is called "Miro" it too can handle a wide range of media formats and is easy to use.
It handles Bit Torrent, 6,000 FREE Internet T.V. Feeds, Podcasts, HD Video, Quick Time, AVI, Divx, H.\264, Windows Media Files, RSS Feeds and almost every other major type of media file format frequently used.
Miro can also download and play You Tube and other FLV(flash format) Video files in HD and it automatically converts them into the mp4 format which many media players can play easily, so you will not have the hassle of using media file format conversion software if you wish to play the files using most other media players.
I strongly suggest you give "Miro" a try, you can download it from
http://www.getmiro.com and many other reputable websites.
Please note that earlier versions of "Miro" did have a few problematic bugs in the software, But I am pleased to say the latest version of "Miro" is much improved and I have not had any problems at all when using the new version.
Anyway I hope these suggestions help you with your problems.