Diversify property management?

[Joseph Weisenbloom]

When managing a portfolio in the same geographic area I have heard of 2 strategies.

1. Split properties between 2 property managers to diversify risk of one failing/going out of business, more exit strategies if one isn't performing, compete the 2 firms against each other etc.

Or

2. Concentrate management under one property manager to potentially get better rates, better service, more attention, better economies of scale.

Which strategy is best? Discuss.