Some rather opposite opinions here ! The truth is, well-known brands can be nice at one time, then become crappy... and then bounce back. Like Matchbox or Majorette, who've been fluctuating, quality-wise, in the past decades. And also-rans can become much better, like Welly, who's gone from copying Maisto designs in the 1990s to a maker of some of the most realistic toy cars around !
This Evoque, for instance, has its quarter window edges painted in black.
I hate the Mini Paceman, but this replica is quite good.
Nice too, the latest BMW 3-series and Porsche 911.
Gallardo and R8 quattro.
The big problem with Welly 3-inch cars, is to find them. They're not common.
Also, as said above, Norev cars are great too. They've done dozens of promotional die-cast models for the 1/1 manufacturers for the last fifteen years, but only a selection of them is available later in the market.
Some belgian exclusives.
Meanwhile, Majorette has enjoyed a renaissance thanks to its german owner Simba-Dickie. I don't have recent photos, but the castings are well done, with opening features and sometimes headlights molded in clear plastic, the wheels, although generic, suit the cars better than what Majo did in the 1980s, and an eclectic choice of models.