Who says "Biocomp is the compost of choice."? The Seller? Does that product cost more money than the rest?
While what goes in to compost does have some affect on the finished product I have never seen any compost worth what some vendors ask for it, and much is not really compost since all that went into it was manure.

Prices are pretty similar for all within $5 of each other.

I plan to start my own compost soon but that doesnt meet my immediate needs!

So, you wouldnt choose any of them?

These products are all from local supplier, A1 Organics, name 'Composter of the year,' by the US Organics council. Feb, 2008.
I was told for the biocomp and some of their other stuff they use 'stuff' from Coors Brewery.

A1 is a wholesaler and their website lists all of their offerings however, the ones I listed above were their only composts avail. from a local retailer.

Really would like to figure this out.

Here is a link that might be useful: a1 organics website

Premium 3 and Evergreen sound like mostly animal manure to me and unless I was sure that had been properly composted I would not use them except as the manure in my compost bins. Pro Gro sounds like screened Evergreen, which may indicate that Evergreen is not really finished compost.
Since the prices are the same I would most likely chose to use Biocomp since that appears, from the description to be have the most inputs which might mean more nutrients in the finished product.