Love the 585 Mini-Barrage for a hard working knife, sturdy and ergonomic (much better than the overly thin handles of many knives this size), performs like a larger knife. The assist is the best I've found in any assisted knife and still closes easily with one hand - combined with the axis-lock, it's among the best truly ambidextrous assisted-opening knives on the market. Plus, the safety switch makes this among the safest folding knives on the market.
Some have complained about the "cheap" feel of the scales, but I have not experienced this, and they are far above the "cheap" feel of the large grips, although they aren't as well textured for maximum retention. However, I have not handled the G10 barrage. If it has better texture, I think that that would be the selling point... but it will be heavier.
Is it worth the price for the upgrade? That's up to you. In my mind, blade-steel would be a better upgrade choice...