Would you keep these tenants or raise the rent?

[John Horner]

So last year I switched property managers on a property in a location that I am not that familiar with anymore.  The current tenants pay $850, but the property manager thinks it would rent for $1050 when we get new renters in.  They are urging me to let the current renters renew at $850 because they are clean, have actually added value to the property (paid for new garbage disposal among other things) and pay rent on time.  

I am thinking an extra $2400/year is something I would be very interested in, but the mgmt company has been VERY good to me and I do trust them.

What would you do?