It's a sector which in recent years has been dominated by restricted machines used on car licences in tourist resorts. However the relatively sporty models coming on the market are pitched at buyers who might have developed a taste for the class and have become serious enough to get a dedicated licence.
One is Peugeot's Ludix Blaster, which claims to be the fastest accelerating 50cc machine. It runs a liquid-cooled two-stroke powerplant with electric plus kick starting, the usual CV transmission and quite wide tyres (120 front and 130 rear) on 10-inch rims.
Piaggio's challenger is the NRG Power (pictured), also with a 50cc two-stroke engine, CVT and so-on., The major difference is wheel size, with 13-inch rims (120 front and 140 rear), suggesting a smoother ride. However it's claimed dry weight is significantly more than the Pug at 99 kilos.
Typically you can buy them restricted to meet special licensing legislation for those using them on car permits, or derestrict them for top speeds of around 90km/h.