I've used POR-15 but have had no experience with the Eastwood product,so I suppose my opinion is biased.
I DO agree with Tim though,the POR-15 is as hard as nails and as long as you can deal with the UV sensitivity,it is a good product.
I cleaned off some overspray on my POR with neat paint thinner and it never even marked the POR.
I also took a bit of 40grit sandpaper to a small dried spill on my workbench,just to see what happened and it hardly touched it!
My 2cents.

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.