Our school used NetCommunity for our Advancement and Alumni pages for about 4 years. We have recently switched to using Blackbaud's Online Express because it is really all we need and it is much more cost efficient for our organization. I also used NetCommunity at the previous school I worked at. I found that as long as someone was willing to put in the time to learn how the product worked it worked great The problems came from users who didn't bother to go through the training and then didn't find it to be "intuitive".
NetCommunity works great for online giving and event registrations. The transactions for both are easily integrated into batches in Rasier's Edge. The registration form is a little cumbersome if there is more than one registration unit involved with the event. Donors thought that the form was too lengthy to fill out. The alumni directory was hard for people to understand and really was more trouble than it was worth. We had to give that piece up when we went to Online Express. Sending emails from NetCommunity works well, although our organization has found that we like Online Express much better for this.There is more flexibility with the design of the email and with Online Express you manage the entire process from Raiser's Edge.
NetCommunity is a good product if need a more total website solution. If your organization just needs to be able to manage emails,online donations and event registrations go with Online Express.