At least for me, the amount of outstanding shares is irrelevant on most fronts. 

I don't care if there are 1.5M shares outstanding like Berkshire Hathaway trading at $130,000 or 10B shares outstanding like Microsoft trading at $30.

Valuation is everything.  The market capitalization decides what the company is valued at by investors not the shares outstanding.  Otherwise, Microsoft would be trading higher than Berkshire Hathaway.

You have me confused here. I understood market capitalization to be number of shares outstanding multiplied by share price. So, 400m @ $1 would be exactly the same as 200m @ $2. The only difference being the number of shares available for further issuance. Say there were 500m authorized, the difference is 100m vs 300m, and this is where it is highly relevant. 100m @ $1 vs 300m @ $2 for M&A.

Would it be preferable to have $100m or $600m?

Be well