Online video sharing sites

[Edit (31st January 2008) - Vimeo has got some excellent new features. You can have password privacy - so anyone (not just Vimeo users) can view your files if they have a password. Also you can elect to have "download original video" switched off for some video if you like. These two options make Vimeo my fast choice now. Plus they allow 500MB a week / per file and no time limit!]
[Edit - Vimeo's privacy options aren't quite what I thought they were. They only work with other Vimeo members - so anyone you send a private clip to would have to sign up with Vimeo - not so good.]

There are loads of video sharing sites - far more than I realised until I looked at sharing the tutorials below. And they all very in quality, ease of use and features.

I have used Youtube - but the quality is pretty poor to be honest (particuarly noticeable with screencasts like those below). However it's easy to use and you'll get lets of people viewing your creations.

Most of the sites transcode your video to Flash format which is ok at higher bit rates but I think looks awful at low bitrates. Video size varies from 320x240 to 480x360 - which is much much better!

Here's some of my comments on some of the sites I've tried:

Youtube:
Pros
Ease of use; huge audience
Cons
320x240; low video quality; no private option

Brightcove:
Pros
Large 480x360 video size (real advantage); high quality Flash encoding
Cons
No private option

Vimeo:
Pros
Simple to use; private options (personal videos for friends and family) - huge plus for me, fast viewing of uploaded files; good quality Flash encoding; can play source file - also really nice feature (although see cons)
Cons
Can download files - not always sure I'd want this

Blip.tv
Pros
Immediate viewing of files; good quality Flash encoding; supports multiple encodings (will convert to Flash, but you can also view your source file and upload multiple formats eg Quicktime, Windows wmv etc) - this is brilliant; if you encode your video directly to Flash you'll see just this (can get far better quality encoding from original file); full screen option generally looks pretty good (it appears that the Flash conversion is very good quality and size which is squashed in the default window size - full screening shows it off in all its glory); lots of upload options - ftp, desktop tool, direct from Windows Movie Maker (download patch from btlip.tvtools
Cons
No private option; didn't find it so easy to use

Summary:
No one clear winner unfortunately. But I'll prolly use Vimeo for personal video because the quality is good and it has privacy options. And may well use blip.tv for everything else. Brightcove is the best quality if the user is never going to download the original or look at the clip full screen so is good for embedding and such like.
Note that I also tried a few others but these were the best I could find.
Also note that screencasting is probably the hardest thing to show in in small window sizes and most of these sites are more geared up for video clips and films. However it's a good test for quality of encoding. Plus I also tried these sites with video clips to confirm my impressions.