Deal Valuation Advice

[Wesley N.]

I'm looking at a property and would like some second opinions. 

It is a mixed use property in a busy trendy area of Chicago on the northwest side. 

The property has one tenant, a successful business, that has been there for 9 years and has 1 year left on the lease, with a 5-year option they intend to use. 3% yearly increases.

The modified gross lease has personal guarantees. The Landlord is only responsible for taxes, insurance, and building shell. 

Tenant has invested almost 200k in the space including an addition on the building.

NOI is $50,500, some deferred maintenance- of course.

What is it worth? What would be a good offer?