I say go with the Fox shock. That thing is very dependable! I had one on my old super 8 and the freakin thing never had any problems. I have an AC also, and I'll admit I was kinda worried about the RS rear shock, but man the thing has been doing well!

The Romic is also a good shock! I have seen issues where the compression damping has blown out. They rebuild it under warranty, but it's kinda frustraiting being without a shock for a week or so.

I tried to order a fox for my AC a while back, and they seemed to always be outa stock of them. The size is the most widely used size so I'm sure that has alot to do with it. If you go with a new shock make sure you don't forget the new bushings for the eyelets, each company has their own size eye...so you need redusers and spacers(bushings) for them.

The 5th element can be a bear to tune if you don't know what you're doing. There are so many adjustment on it, it's tuff to keep track of what your doing. It's a great shock for a racer, but honestly for all around riding it's just to much. Dont get me wrong I love the design and the shock itself. There's just alot of tuning to do.

Well let us all know what you end up getting and what you think of it!

Just outa curiosity why do you need a new shock anyways? Maybe that could also help us point you in the right direction.