At this time the pier is not being dived at all. Coral Coast Dive has closed their doors completely. As things develop, I will post a reopening of the Pier & details.
The Pier is a great fish dive. There's no corals and no reef structures (though there is a lot of neat, colourful stuff on the pylons) and you pretty much never see turtles and such. But there are a ton of fish all in one little area. There isn't much there that you wouldn't see on the reef, but on the Pier is it more concentrated and very predictable. The vis, like anywhere, can be great or crud...but it doesn't matter much (same as on the reef as long as you have a good guide or go nice and slow on your own!) as there is always something to see.
The Pier is pretty expensive $95/single dive during the day - max time is usually 50 minutes. Three years ago it was about $50. It has had the most severe price increase of all the diving/tours offered on the Ningaloo & surrounding areas. i would not expect much of a price change when the Pier reopens, but there might be one.
If I only had one day to dive from Exmouth, I would not choose the Pier - I'd dive the reef for sure. But if I had three days... On some days you can actually head out in the morning and do the reef and then do an afternoon one on the Pier when you get back...the depths are good for three dive/day but you have to choose your day as the Pier is tide dependent.
Anyway, I am rambling...happy to help and will post as soon as I know anything.