Just my take - but I think it all depends on what you are interested in with regards to services/features. For me, the appealing thing about WU (when it was actually working) - was the ability to figure out what was coming my way weather-wise. I do a lot of duck hunting in December on the St. Lawrence R - which can be decently dangerous if you get caught out there in unexpected wind. We also get a fair amount of freezing rain here in the winter - and it's nice to be able to see temperatures/conditions locally. We lose power a lot - so its nice to pump the heat up if there's a chance of an outage.
So, basically, what I would be looking for is hyper-local conditions in real time - not necessarily forecasting. The weather network/channel forecast is hit and miss - but good enough to get the general idea of what is likely to happen - at least around here.
To get the hyper-local conditions you need lots of members and lots of stations uploading reliably - which was why WU appealed to me. Nice to be able to see the cams as well. I'd pay for that service if it was reliable and easy to use.