I would call Opti-Coat or Opti-Guard a very long lasting (if not permanent) wax.
It does nothing to protect your car like 3M ClearBra does. It offers the benefits of Wax but in a longer term. Paste wax usually doesn't last very long.. 1-5months I've seen from different waxes and sealants.
Applying Opti-Coat when the car is brand new is a good idea because the paint is still in good condition. Once the paint becomes scratches or marred it becomes more difficult because you need to correct those problems before applying Opti-Coat (since it's permanent)
I'm not sure why detailers charge $$$$ for applying Opti-Coat ontop of a regular paint correction detail. It really isn't that hard to apply... With a longer curing time than Opti-Guard you shouldn't make any mistakes if you follow the instructions carefully and do your research. I'm not sure if people know but Opti-Coat is only $60 for an fluid oz.
http://optimumcarcare.com/ocoat1.php?li=4
You can treat it like an extra layer of clearcoat but slicker and repels water and dirt like wax. Or you can treat it like a permanent layer of wax. The difficulty doesn't come with the application of the Opti-Coat but the paint correction that needs to be done before the application. Can you DIY paint correction? Of course you can. You need to do research and invest in products and equipment though. If that isn't worth it to you than pay someone to do a professional paint correction and apply Opti-Coat.
I've applied Opti-Coat on my car before but decided to polish it off as I like to go over my paint often with fine polish to bring the luster back out. Plus I love the shine and sheen of high quality paste wax. Something that I haven't found with the Opti-Coat. Of course you can put paste wax on top of Opti-Coat. Products like Collinite have given me enough durability so far to not feel the need for Opti-Coat on my own car. Opti-Coat is perfect for those who don't have the time or money to detail and wax their car every few months. You can apply Opti-Coat and it'll last you a very long time. Regular wax will fade with regular car washes, Opti-Coat is not going to (at least we don't know for now - hasn't been out long enough to see if it really does last forever)