Is anybody using Wikispaces for student e-portfolios?

It's problem after problem with them.

First it wouldn't run videos embedded in IE7.
So we installed Firefox to overcome that.

Then, different video formats would not embed resulting in us converting from avi to mpg and now finally to wmv which "seems" to work.

Latest catastrophe is now when all the kids in the class are uploading either pics or vids the entire site slows to a crawl, often freezing the browser.

Anybody with other tales of woe (or success?).

Sounds like powerpoint is the way to go next time...