Help me evaluate this 4-plex deal

[Tim M.]

While technically not my first deal, this may be the start of my RE portfolio. I'll run through the numbers, feel free to comment/advise,etc.
4 unit MFH, asking 105k. I will offer 97k max, I have 30% cash downpayment and have secured financing for remainder. I believe seller will accept offer. Long story short, it was previously condemned (extended vacancy led to mice/roach infestation, then taken over by township and remodeled up to code. So virtually everything is new. Walls, floors, siding, counters, utils, etc. Currently fully rented with leases for last 3-4 years. Its in a good rental area and is priced 5-15k under comps, as well as units are newer/nicer than comps. I'm guessing the township just wants it off their hands, and could probably use the lump payment. Here's some numbers:
GOI (minus vacancy) = 21240
NOI = 10620 (50% rule), however, because everything is new, NOI could actually be near 70% with no cap expenditures in the near future.
Cap rate = 11% minimum
cash on cash return = 25%
I have a side deal with my brother/partner where he would be property manager but would forgo any payment in lieu of earning equity in the property - I can explain more if anyone is interested. This would be a buy and hold for about 10 years, then we'd decide wether to sell or keep holding at tnat time depending on market. What do you think? Should I jump in? Pros, cons, questions in this scenario anyone?