Upload & Sell: Off
Each paper manufacturer has slightly different variations of each style of paper.
It should also be mentioned that minilabs and pro labs use different papers for different needs and name their products (and surfaces) for what the consumer or professioanl desires. For example matte paper run through my consumer lab is actually lustre (which does not fingerprint), while matte in the pro lab is a true matte.
In my prolab I print only on Fuji Crystal Archive Professional Papers so I'll address those specifically.
Glossy (type C): Medium gloss; higher color saturation and contrast than most other surfaces.
Matte (type C): Flat surface with a slight sheen, because this is a commercial paper it has a higher level of color saturation and sharpness than consumer matte papers.
Lustre (type PD): Slightly pebbled finish resists finger prints; slightly lower in saturation and contrast, ideal for portraits and softly lit landscapes.
Pearl (Fuji's name for metallic): Medium high gloss; High color saturation, contrast and refraction. The addition if reflective "mica" beads in the surface add an pearlescient effect (hence the name). Great for brightly colored scenes, cars, motorcycles and fashion shots.
Fujiflex (for me, special order only as it cost nearly $1000 a roll): Super high gloss, similiar to the old Cibachrome A surface paper. Super saturated and vibrant. Use for commercial displays where the ultimate in "pop" is desired.
Deep Matte (coming June 2009, again special order only because it is $800 a roll): A very flat surface. Slightly lower contrast because the surface absorbs and scatters light. Hard to describe this one still, from the samples I have played with it is like a very expensive heavy bond printed book.
Each of the labs you have mentioned plus myself also offer paper/printer profiles for use in softproofing to get more accurate results.
Also, each lab is tied to a type of printer to best meet the needs of their clientelles.
Millers, Mpix, WHCC use Durst Theta printers for their larger format printers (WHCC uses Noritsu Commercial Minilabs for prints smaller than 12x18, this is important as they might be set up as sRGB printers rather that Adobe 1998 RGB which has a wider gamut). Bay Photo Labs (not sure of thier printers but I believe it is a mix of Durst, Fuji and Noritsu) has set up their printers for sRGB.The durst printers are exceptionally well suited to portrait output (weddings, etc.).
Most art labs such as West Coast Imaging, The Slide Printers and myself use Chromira printers which are better suited to commercial (and fine art) output. Chromira's are also by default wide gamut Adobe RGB printers.
When your ready to get going drop me a line and I'll send you a paper sample packet.