I looked at the features offered by CF a few weeks ago and wanted to use it on my website.  But I had concerns like yours about a number of items.  For these concerns I don't have documented proof that there would be a problem but when I don't have proof that something is good, I don't use it.

For example....

CF can rewrite some of my outbound links and install affiliate code.  What will google think of that?

Let's say I have a retail site and don't want to ship outside of the USA, so I tell CF to block ips from all other countries.  Will that cause a problem when lots of people see my site in the SERPs but when they click into it  they are blocked?

When they optimize all of my images and move them to other servers will that cause a problem for me in image search?

If my site is on servers in other countries will that influence my rankings?

I read reports where other people put their website on CF and it was actually SLOWER.

These are just a few.  And, I am not saying that these are "bad".  Just saying I don't know for sure what the impact will be and when I have this many concerns about something I don't use it.

Now, if somebody has great things to say about the above to clearly say that my concerns are unfounded, I would like to hear them because I really like what this product can do and I would like my concerns to be eliminated so I can use it.