What rate for 30y mortgage w/25% down 420K invest proper 3units

[Najat F Kessler]

This is my first post here so please be gentle :D 

I am looking to buy my first investment property. A 3 units multifamily at 420K, brings in over $3700/month. I got 5.99 as a rate for a 30 years mortgage.  Should I shop around or is this a good rate? I have a credit score above 760. 

Please enlighten me.

Thank you,

Najo