What do you currently have?

How locked down is your company phone? A dual SIM phone allows you to carry one device and seperate call charges, but if your company's usage policy stops you from having personal apps on the phone, that could be a probelm.

Are you expected to work internationally? Some phones (less now than five years ago) don't work outside the US. Some carriers have better foreign roaming deals. For example, TMobile includes throttled data in over 100 countries, limits calls in those countries to $0.20 a minute, gives you unlimited international texting; and supports wifi calling for no roaming fees.

My opinion is cross-polinate your carriers. It will double your coverage issues.