Questions about Grou.ps

Hi,

I am trying Grou.ps with a class this semester and so far, it's not been working out well. My students did not get the invitations, then when I resent them, they had passwords problems. The site is a bit slow to load. But I still would like to use it because I love the features it offers and I feel it could be a great substitute to NING. I'm also using a NING mini in another class and it definitely does not offer some things thatI would like for this class.

So, my question is, is anybody using grou.ps successfully? Is this just growing pains that I am having? Is it worth trying longer?

Any advice or stories are welcome!