There is a lot of comparisons, but the most convincing one maybe the LEGO Ferarri (42125) vs. CADA Italian Super Car (C61042W) video[1] of "Held der Steine" (german youtube channel). The LEGO is "parts only" - the CADA is remote controlled with led lights near double the parts of the lego one for the same price.
Many of the newer manufacturers are 100% compatible and provide near double the part count for a similar set. Even if some of them are shameless rip-offs and illegal to have in some countries, most of them are smaller companies with great part quality, prints (no stickers) and innovative designs (see CaDA® C61503W AMG One).
There is also the world of Trains or Tractors, where LEGO tends to fail every time.
There are
- CaDa
- BlueBrixx
- Cobi
- fischertechnik
- Unico
- Mould King
- burgkidz
- Wange
- Sluban
- Q-Bricks
Just to provide you some alternatives :-)