They both sell for 50k. He sells 50 B2B products and she sells 5 B2B services, per month. WHO would you hire as the BETTER B2B sales professional?

Basically it depends on the vision and mission statements of the organization. However if  given a choice I would prefer the one selling service for the very fact that a service which is intabgible in nature is more or less a bit of a challenge than the sale of a tangible product. Other than that it would be the job of the hiring manager to decide on the inherent accumen of the sales person to be able to sell and not only on what is the quantity or the product sold in earlier organization.

Depends on the critieria you rely on when making this assessment.

1.  Is it the revenue ???   they are the same inyour example
2. Is it the focus on services (maybe) because services have higher profitability than products ?
3. Is it the number of customers ( assuminlgly50 vs5) and the potential of growing business with thm ?
4. Is any of these customers in either case a strategic value account (more business in the future) ?
5. Is any of these situations a tough win-back from competition ??

So, it really all depends as you see !

I will hire first the one with50 B2B product sale...

Bcs in sales, we need purchase, a bigger bulk order of future forcasted sales could be more profitable, so it is better to add a staff like him......