Well, my past employer/lessor had tested some ProStar+ trucks with this particular motor and they too had nothing but horrible things to say about it. In fact, it was in the shop more than 3x as often as it's worst SCR competitor, due to problems with International's Massive EGR system. They found it was best suited for short-hauling containers in their new intermodal division, not doing team expedited LTL work or OTR work with owner/operators.
The Pete 587 and KW T700 were the worst SCR competitors, but their issues were mainly due to ride, quality, driver ergonomics and fit/finish, not engine problems.
The International and PACCAR trucks dismally failed for a team LTL operation when they were tested, and the drivers at my past employer chose an unlikely candidate: the Volvo VNL64T 780. Some of them were spec'd with the XE13 fuel efficiency package. Though there were a few "bad apples" in that test fleet, the Volvo 780 and 780 XE13 delivered very high fuel economy- even without I-Shift and the XE13 upgraded powertrain- and for the most part, the testers loved how the Volvo VN 780 was set up. The DEF tank was almost a non-issue, just like adding engine coolant or washer fluid. And the drivers loved the smooth, remarkably quiet operation of the Volvo truck.
Massive EGR is not suited for LTL and OTR operations because of the amount of passive regeneration it needs to do when going down the road. In fact, it works better (is more reliable) if you haul heavy. Parked regeneration was quite common with the ProStar+, as were issues with EGR valves, turbo chargers, leaks and computer problems. The test drivers also did not like the lack of power, even when it was turned up (they sometimes called it "Lacks-force" or "MaxxFarce"). You would effectively have to re-learn how to drive with it.
The fuel efficiency? It was nowhere near International's claims. MaxxForce had a 5.5 MPG average (versus 7.1 for the pre-SCR Detroit DD15, PACCAR MX and Cummins ISX, 7.5 for the DD15 with SCR, 8.1 for the Volvo D13 and 8.2 for the Volvo XE13 with nearly identical power specs on the engines).
Do yourself a favor: stay away from MaxxForce (for now) and wait until the 2014 revision comes out. If you can't wait for MaxxForce with SCR, and you must have a brand-new factory-spec truck (assuming you live in California, work for a fleet with a 5 year rule or you are independently wealthy), bite the bullet and switch to a truck with an SCR-equipped engine.
The Volvo VN 780 (and VN series, for that matter), Freightliner Cascadia and Mack Pinnacle, along with the above-mentioned PACCAR/Peterbilt/KW products, seem to be far more reliable than the ProStar+. Although I hear of a few gripes every now and then (P$$$ tank is a commonly heard phrase for DEF tank), most of the drivers seem to only have praise with how well SCR was implemented.
I often joke about how often I see the brand-new trucks sitting roadside waiting on a tow, and that's definitely the case with Internationals with MaxxForce MEGR.
Your best option? Get a glider kit or used truck with a rebuilt CAT, Cummins or Detroit engine. Those seem to be far more reliable.