Well, I appreciate all the comments here & inputs I have received via PM's.  I decided that I wanted to try an internal frame pack because of periodic pinched nerve issues that I have with my back.  That decision quickly narrowed the field down to Granite Gear's "Nimbus Great Northern" and Ostrom's "Wabakimi".  

Both bags are pricey.  I'll agree w/Red Lake Rob & state that the Ostrom Pack is clearly the better made bag of the two.  HOWEVER, I wasn't sure it was really worth the price difference.  The Wabakimi retails in excess of $475 American versus the generally listed price of $319 for the Nimbus (which only this week went on sale for $255 w/free shipping from MooseJaw).  Well, I've made my decision about that value differential & I'll get around to sharing my selection in a second.  First, though, I want to share the key thoughts that kept ringing around my head in advance of my decision:

Mad Mat:  "A bag is a bag".

Ranger (via IM):  "I'd find it tough to pay almost $500 for a pack. One way to think of it is: you could almost buy TWO Nimbus packs for the price of the Ostrom. Are their useful lives going to be that much different? Is their respective utility going to be that different?"

Tooth Fairy: "I have this pack [Nimbus], have had it for 2 years and I love it.  Costly but worth it."

Yes, you've guessed it.  I went with the Nimbus Great Northern, after all.  That special sale on gear through MooseJaw put me over the edge.  The price differential was just too much to ignore, so my new Granite Gear bag is on the way.  Hopefully the internal frame concept will help with my back issue.

I suppose I am somewhat at risk of having buyer's remorse when I amble past the Ostrom display at CanoeCopia next year & eyeball their primo Wabakimi bag with all those doodads & its superior construction.  Red Lake Rob is right; it's TRULY top-of-the-line.  Nevertheless, MM's profound sagely advice - "a bag is a bag" - haunted me back into fiscal responsiblity... and that ain't easy to do when it comes to my free-spending ways with canoe gear.

Next on the agenda: a good pack for my solo canoe.  Of course, this one is easy... CCS's "Explorer Pack" all the way!

Again, thanks for all the advice!

Jimbo   8-)