The Mk7 / 7.5 GTI (2015–2021) is, for most, the high-water mark — the MQB platform, the sorted EA888 Gen 3, a fabulous chassis, and the Performance Pack with the VAQ diff and bigger brakes.
Engine: the 2.0 TSI (EA888 Gen 3) — the most reliable of the turbo fours, with the earlier faults largely designed out; a couple of hundred hp on a Stage 1 flash.
What defines it: the complete package — pace, handling, usability, reliability and huge aftermarket support. The Mk7.5 facelift refined it further.
Owning one: water pump, wastegate rattle, DSG/VAQ service (Buying Mk7 GTI).
Bottom line: the one to buy — the best all-round GTI yet. See Mk8 GTI Overview.