Ok, I'm sure its something obvious. But I am not that familar with braid.  What is the difference in these two?

100M 90LB MAXX POWER PRO BRAID Fishing Line DYNEEMA

http://cgi.ebay.com/100M-90LB-MAXX-POWER-PRO-BRAID-Fishing-Line-DYNEEMA-/320670262974?pt=LH_DefaultDomain_0&hash=item4aa96fe6be

(I know this is not "Power Pro")

Powerpro braid 65lb(moss green) 300yds

http://cgi.ebay.com/Powerpro-braid-65lb-moss-green-300yds-/180639717149?pt=LH_DefaultDomain_0&hash=item2a0ef7571d

I know the obvious things, color, #test, stuff like that. 

I imagine one is probably for saltwater or some other type of fishing where casting is not as much of a problem?  I don't know.  So, how do these compare and contrast.  I see dyneema and spectra a lot. What does this mean? And is there a reason I couldn't or shouldn't use this on a baitcasting bass set up?  (not neccassarily the #test, just the two types of lines in general)

One's a re-packaged spider wire, the other is Power Pro.  Dyneema and Spectra are two different fibers with two different methods of spinning to get a completed braid.  As for the two types of line, both are suitable for use, some will claim large difference, some will claim none, saying it's the same thing.  Chemically, both are polyethylene, in other words: the same.  The finishing process is the only difference; the way the line is spun then braided, and eventually coated.

Hmm... Thank you very much.

You say a re-packaged spiderwire.  I had once heard rumors of it being more flat and would not lay aw well on the spool and such....  Is this true?  I currently use power pro....how is this stuff (if it is re-packaged spiderwire) going to differ from power pro?

I'm not terribly familiar with spiderwire.  I've never used it, really.  I've always used Tuffline, Gorilla Braid, or Power Pro.  In anything that I've seen, not experienced, Spiderwire is harder to manage, it doesn't pack as well on the spool, and it doesn't lay as even as other superlines.  That's not firsthand experience, though.