Embraer Legacy 450/500 & Praetor 500/600
These Embraer jets filled the gap in the product line-up between the Phenom 100/300 and Legacy 600/650, competing in the already crowded "super mid-size" class. They have the familiar shape: low wings, T-tail and engines attached to the rear fuselage. Thus easy to confuse. It is best to look at the tail, because like on the Phenom 300 the horizontal stabiliser seems to be tilted forward.
EMB545 Legacy 450 & EMB550 Legacy 500
The first generation has two versions, differing mainly in length (1.2 m). The smallest is the Legacy 450, which has six cabin windows on each side. The larger Legacy 500 has seven or eight. Compared to the second generation Praetor 500/600 the winglets are smaller. They start about halfway the wing tip.
EMB545 Praetor 500 & EMB550 Praetor 600
Embraer felt that the Legacy 450 and Legacy 500 could be improved by upgrading engines, increasing fuel capacity and making the winglets taller. The latter already start at the wing's leading edges and are the way to distinguish the Praetor 500/600 from the Legacy 450/500. The differences between then Praetor 500 and Praetor 600 are the same as between the Legacy 450 and Legacy 500.
Confusion possible with
The closest competitor in terms of external appearance is the Hawker 4000. For recognition again first look at the back of the engine nacelles, as the Hawker has fairings for thrust reversers, the Embraers have not. Also the Embraers have winglets. Smaller differences are in the closely the cockpit windows, dorsal fin and tail.
The G280 is bigger than the Embraers and more thus cabin windows. The Gulfstream also has a short dorsal fin, but lacks the typical top of the vertical stabiliser of the Embaer.
Like the similar aircraft above Citation Longitude has different cockpit windows and is a bit bigger. There are also smaller differences to allow recognition from the Embraers, of which the strakes underneath the horizontal stabiliser (on the Cessna) are one.