I can only speak for the PC Connect, which I have, and have had no problems at all with it. reading the Acurite forums, the Hubs have been creating a lot of issues right now as they migrate something on their servers.
For WU, your PC will need to be on all the time.
I have an Acurite display, which is always showing my data, even when using my computer for other things. If you are going to get a computer for only weather, it could probably serve as a display all the time as well.
Hope this helped some. Good luck!