Chances are if you're thinking of watching this you're a fan of Sergio Leone's films and the Italian western. That being the case, I'd recommend Django but suggest you manage your expectations.
First, the similarities with Leone. You see a lot of familiar faces from the Dollars films. There's also plenty of ingenious and well orchestrated violence with some very clever set pieces: the gun battle in the muddy town (overtones of WWI here?), the fist fight in the saloon where the camerawork is incredibly mobile, especially for the period. Plenty of the aesthetics are familiar too from the sound effects (the gun shot sound is exactly the same) to the sets which were designed by Carlo Simi (here credited as Giancarlo), though in the latter the differences creep in. Instead of the dust dry south-west, Django is set in the lush and wet mid-west.
However, many trademark aspects of Leone's film making are missing and here the comparisons are not favourable. The most obvious difference is that Django wasn't shot in Techniscope. It makes a huge difference to the look and feel of the film. Also absent is Leone's appreciation of grotesque physiognomy. The other sorely missed element is that the score wasn't written by Morricone. It's impossible to stress what a difference this makes. Even Morricone's less successful music, say in Once upon a time the Revolution, adds a cohesion and mood to Leone's films that is unique. That said the title track of Django is a winner!
What about Corbucci in his own right? He certainly has some moments, from the opening sequence where Django is dragging a coffin through the wilderness, to the moment when he reveals its contents and when the `red masks' invade town. Franco Nero isn't Clint Eastwood but does brings a silent charisma to the part.
Django is a must see for fans of the spaghetti western but it's very much second league in comparison to Leone - which maybe an unfair comparison. A huge number of sequels were made, though only one 'official one' (in the late 70s if I recall) though I suggest these are left to the aficionados only!