2005-2015
how do they compare in terms of reliablity, ownership costs and maintenance?
Ownership Costs
1. Porsche
2. BMW
3. Infiniti
Reliability
1. Tie between Porsche/BMW
2. Infiniti
If you are considering any of these, I would recommend having cash set aside for repairs...and I mean a few grand, not a couple hundred bucks. You don't really buy any of those for reliability to be honest. It's more for luxury/fun to drive with reliability being the trade off.
How much money and time do you have? Without info on specific models, it's hard to be accurate, but suffice it to say that all of these makes will require expensive maintenance to achieve "reliability."
Between those three, Infinity would have lower total cost of ownership (TCO).
#1 being the most expensive to maintain. As @Daywalker said, ownership-wise the Infiniti is going to be much cheaper, with Porsche being highest and BMW second. Bear in mind that it also depends on which models you are looking at. Infiniti will always be cheapest regardless, but BMW/Porsche could swap spots if you start looking at anything in the M-Series or 7-Series.
In terms of TCO, from expensive to less expensive:
Porsche (real Porsche): because often times you have to drop the engine for maintenance. Not sure when that started, but it has become a thing.
BMW: while the core engine/transmission, parts and labor cost an arm and a leg. And so much little shit eventually breaks, that it adds up.
Porsche (VW platform): my guess*** is that since it shares components with more mass produced VW’s (VW, Audi, Lambo), it may be less expensive to find parts. Still expensive though.
Infiniti: Infiniti shares its platform with Nissan and the Renault group. So there should be tons of parts available depending on the model. And Nissan are usually easier to work on, but this is just a guess that it translates over to Infiniti.
