Is this a good deal? Help me analyze it please!

[Bryan Holland]

I'm looking to purchase my first duplex.  

Remodeled single story duplex in established residential neighborhood.   For sale by owner. No immediate capex or repairs needed. I would manage it myself. 

Asking Price 475K 

Each unit is 1250 sq. ft. 3bed/2bath with small backyard and garage 

Remodeled kitchens and bathrooms.  Tile and laminate flooring

Occupied by tenants who are paying 1800/month each and pay all utilities and take care of yard maintenance.

Landlord pays water/sewer which is 190/month

Im thinking of offering 450k with a 20% down payment in cash of around 90000-100000 and carrying a 30 year loan with a mortgage payment of around 2075/month (tax and insurance included).

It seems it would cash flow 1525 a month before accounting for maintenance, capex, and vacancy percentages.

Am I calculating this right?  Any ideas?