The McLaren MP4-12C, to call it by its full name, is a car with a number of flaws when it was launched. The interior and exterior are decidedly average and due to the rush to get it into production, several things initially did not quite work. They were all fixed over time thankfully but the car is known as struggling to create much emotional bond with the driver.
When you get inside, you may not like the choice of leather, the shape of the steering wheel or the UFO-like instrument binnacle. It is down to individual taste.
Compared to the more recent offerings like the 720S, the original 12C decidedly lacks sharpness in every area such as throttle response and suspension (in pitch and roll). Its 590+ HP power figure and 440+ lb*ft torque made the Ferrari 458 feel slow but how the power was delivered was not necessarily exciting when compared to a naturally aspirated engine.
By 2020 standards the gearbox software control is not that nice to drive: not particularly quick or refined but for sure better than the systems of Aston Martin or Lamborghini (e-Gear).
As prices of the 570S start to be close to those of the 12C, the 570S would be the better car to drive. In terms of "general sharpness" McLaren has probably lagged behind Ferrari even now, when you compare for example the steering wheel design of the 488 Pista versus the 765LT.
The "Tenneco Kinetic" suspension system is reasonably reliable. Accumulators can fail if the suspension has not been allowed to keep pressure. If the car feels like it is running on its bump-stops then it's probably because the system is lacking in pressure. The cost for a full set replacement is approximately £2000.
The Adaptive Damping system is set up via calibration tables so that it adjusts damping based on driver inputs. The pressure level in the system is selected by the driver via the Normal, Sport, Track mode switch. The McLaren impressed for the way it handled very uneven roads very quickly. This however makes it overall a less enjoyable car to drive than the Porsche 997.2 GT3 of the same era.
The approximate production numbers are presented for different years:
2013 delivery: 1359
2012 delivery: 1200
2011 delivery: 400 units
Some second hand prices:
£69k, 2011, 16k mi, white
£70k, 2011, 22k mi, black
£70k, 2012, 12k mi, white
For comparison, the most affordable second hand 570S are advertised for £80k to £85k.
https://www.thorneymotorsport.co.uk/shop/mclaren/12c/