Thanks again to everyone for their compliments and suggestions.
New Years update:
The concrete contractor just applied the solvent-based clear sealer to the acid etched concrete floors. They use the Stain-crete system, but other acid staining options exist.
I really had a difficult time deciding what to do with the concrete floors.
Bare concrete: Looks good when new. Eventually stains and darkens.
Plastic tiles (i.e. Race Deck): Looks nice but covering 1900 sq ft with a "floating" plastic floor didn't appeal to me. I may still use these tiles in discrete areas.
Quartz ceramic tiles: The ultimate look. Way too expensive (no offense, Ultgar)
Vinyl tiles: I grew up in an old home with lifting, cracking linoleum tiles. It's a lot of labor for a product that has dubious durability. I can just picture the unpleasant process of stripping the adhesive if it didn't work out.
Epoxy based paints( i.e. Griots, UCoat-it) Impressive looking apllications. Solid color floors look great. Cost is reasonable. However, even when applied professionally with impeccable preparation, these finishes eventually fail. Period.
Acid stained finishes: Metallic salts in an acidic, water-based solution react with hydrated lime (calcium hydroxide) in hardened concrete to yield insoluble, colored compounds that become a permanent part of the concrete. The color becomes intergral to the concrete and will not chip off. The finish has a variegated, marble-like quality...you may or may not like the look.
Acid based finishes are pretty cost effective (about $3.50/sq foot). It is usually topped off with a UV stable, solvent based clear coat that can be reapplied anytime later.
Downsides? Color options are generally limited to "earth tone" colors like tan, brown, green.
Well enough talk.

Here are the pics: