This asymmetric three-door splits into two personalities: buy the base 2.0L and you get a buzzy economy car that looks quick but drives like it's apologizing, while the Turbo and especially the N deliver genuine hot-hatch thrills that embarrass cars twice the price. The 2013s grenaded engines with rod knock and bearing failures, avoid completely. Later first-gen models (2015+) and the second-gen (2019-2021, now discontinued) are far more solid, but every year suffers from comically persistent horn failures that need replacement after replacement, even under warranty. If you're considering a 2015+ Turbo or any N, commit to 4,000-mile oil changes and accept the horn lottery, you'll get a legitimately fun driver's car for used Civic money. Skip the base model unless you need cheap transport and nothing more.
The Mazda3 is what happens when a compact car decides it's too good for its price bracket, and the interior actually backs it up. The 2.5L engine is bulletproof (owners routinely see 200k+ miles), but the 2019 redesign swapped the old multilink rear suspension for a cost-cutting torsion beam that blunts the handling sharpness earlier models were loved for. If you want a refined daily driver that feels expensive and runs forever, this works; if you want the sporty Mazda everyone raves about, hunt down a 2014, 2018 instead.