White Labs and Wyeast advertise 100 billion cells per container. Fermentlist advertises a minimum of 6 billion cells per gram (69 billion total cells) at time of packaging.
To better understand the yeast pitched, over the last several weeks I have been doing cell counts on yeast purchased from the local home brew store.
Viable cell count
77 billion *
153 billion **
* rehydrated in cold water for about 5 minutes, then stirred in.
** rehydrated in 77°F water for 30 minutes, then stirred in.
These three yeast cover a very wide range of yeasts: both liquid and dry, brewers and wild strains. There was very little actual content in the WLP650 vial compared to what you might expect with a typical brewers strain. Microscope examination showed that the cellar morphology of these two are very different. The WLP862 looks like a typical brewers yeast: spherical and 15-20 micrometers in diameter. The WLP650 was football shaped, although there was some variation in cell shape. They also appear to be much smaller at about 7 microns in diameter and about 10 microns long.
The US-05 looks like typical brewers yeast. I was surprised that the viability was so low. This might be due to the rehydration method deviating from the manufactures recommendations. Although this is not a problem as the viable cell count is high enough.