I'm probably biased to Stern machines, as Stern are an established company.  I expect all these new companies will suffer reliability problems in the their first few years.  I'm keen to see what the future holds, as I can't see all these new boutique companies surviving.  That said, JJP games do look stunning!  And they have got past the biggest hurdle for a new company: being able to get to a second machine!

One thing I don't like about the JJP is their approach to their boards.  They have gone down a PC path.  There is good reason why Stern, Williams & Bally amongst others never did that.  Every year or so, some of your boards go out of production.  So you never have a long run of a consistent set of boards.  To the owner, this means that it will be hard in the future to get replacement boards.  The boards will be slightly different if you are lucky that will only require new drivers of firmware patches to existing boards to maintain compatibility.  Get it?  Stern build their own boards, and can keep on doing it for years, until they decide to do an upgrade.  JJP is at the mercy of suppliers who keep updating as their customers always want the latest/fastest board-sets.
 
I understand that the Hobbit board set is an evolution of the WOZ board set.  Will JJP game three be different again?  If so, I'd recommend that buyers who intend keeping JJP games long term, buy spares within the first few years of buy a JJP machine.

...Have I got this wrong?  If so, please correct me Mr Pinball, JJP or anyone else who would understand the JJP board set better than me.

(I loosely recall reading that Homepin are developing their own board set, stating reasons as above for not using PC based systems.  Wise choice!  I think Spooky pinball would be the only other company with their own board set.  Others are using PROC which is better than a PC, but is still dependant on a supplier.  Not sure about Heighway Pinball.  When buying, this is a question worth asking if you are a buyer and holder.)