Mulit Family Deal Advice

My husband and I are considering our first multi family deal. 

I would appreciate any advice and guidance from more experienced multi family investors. Here is the information I have so far:

It is an 8 unit (4 duplexes) property. Four units are 3/2s ($800/month) and the other 4 are 2/2s ($750/month). It has been on the market over 300 days and the owners live out of state. The property is being managed by a local property management firm and according to the listing agent, it hasn't had a vacancy for more than a day in over 5 years. Units are currently fully occupied. Built in 2000.

Ask price: $780K
Appraised Value: $780k (unconfirmed)
Offer: $700k
Down payment: $115k (25% equity position)
Loan Amount: $585k
Closing Costs-$8k
Interest Rate: 4% (unconfirmed)
Term: 30 year
Monthly P&I: $2792.88

Monthly Income: $6200.00
Monthly Expenses: $4467.88

Monthly P&I-$2792.88
Vacancy-$124 (2%)
CapEx-$310 (5%)
Property Taxes-$931 (15%)
Repairs- $310 (5%)

Monthly Cash Flow: $1732.12
Cash on Cash Return: 17.47%

• These numbers assume we will be managing the property as we do not yet know what the property management firm charges and offers.
• We have not yet had a showing of the units, although I am familiar with them and the neighborhood.

Any thoughts on this deal? What else should I ask/do/consider before deciding on making an offer?

Thanks in advance for the help.