We have a 2015 LE 4C, an early production '17 QV and an '18 Stelvio ti.
All are completely different drives, but they are all best in class, IMHO.
The 4C had some issues when new, which Alfa sorted out. About 20,000 miles now, a few tracks days, fairly spirited road driving and most of the mileage with the Pogea Stage 1 Plus tune/exhaust installed. and its been perfect and never a code or problem since Alfa sorted the initial issues out at around 3,000-4,000 miles.
The QV has about 17,000 miles on her, no issues at all except for a quirky nav system when brand new (sorted by the dealer first day with flash update), a squeaky CF driver's seat (replaced by the dealer at about 6,000 miles), and a poorly adjusted hood release (adjusted by the dealer). Its my daily driver. I'm on my second set of P Zeros, which are pretty dicey (kinda' like hockey pucks) below about 55 degrees. Will put Michelin 4S's on for the next set.
The Stelvio has about 14,000 miles now, and has been flawless. That's my wife's DD, except when she decides she wants to play in the QV for the day. Under these circumstances, I am forced to drive the 4C.