The “Classic” Actifry model, first released in France in 2006, is still in production, but has been joined by at least 8 other models (as of August 2014.)
This is a list of the models I know of as of 2014, listed roughly in ascending order of price / features. [2018 note: this list will be updated in the near future.]
You can click the model name for an overview of the product.
List of Actifry Models
Miscellaneous facts about Actifry Models
The Actifry was first launched in 2006, in France. Groupe SEB. History of Innovation. Retrieved August 2014 at https://www.groupeseb.com/en-en/history-innovation.
Actifry is sold under at least two brand names: Tefal / T-Fal, and SEB. SEB is the “mother ship” company of Tefal (and several other kitchen appliance companies such as Moulinex, Lagostina, All-Clad, etc.)
In some parts of the world, the Actifrys are 110 V, in others 220 or 240; it depends on the country that it was adapted for by Tefal.
Most models, confusingly for many people, offer 2 buttons to open the lid – one on either side of the handle. People get confused which button to press, or if they have to press both at the same time. The Actifry Family just has one button, to the right of the handle, so there’s not a whole lot of doubt about which button. Though perhaps a choice of buttons is more friendly to the lefties amongst us.
On models such as Actifry Family and Actifry 2 in 1, when you open the lid, all cooking stops — both the paddle and the hot air, as well as the timer counting down. On the Actifry Classic, when you open the lid, the paddle stops but the hot air keeps going, as well as the timer.
Confusingly, the symbol they’ve chosen to use on some models for the “GO” button (after setting the timer) is the universal (in North America at least) symbol for power off / on.
Units that come with a collar (as of 2014) include: Actifry Family, Actifry Plus, and Actifry Mini. The collar is sometimes referred to as “Overflow prevention ring” or “turn-over” ring.
For all models, I would recommend getting rubber tipped tongs such as those made by Oxo Good Grip so that you don’t scratch the pans or grilling trays.
The lids and viewing windows generally stay free of steam (somehow) but if there is enough built-up gunk on the inside of the lids, they can fog up.
Overall, the common negative observations about the models is (1) their size — the size they take up on increasingly-crowded countertops — and (2) the noise the hot air fan makes.
By the end of 2013, 6 million of all Actifry models combined had been sold around the world  Groupe SEB. History of Innovation. Ibid.
* Actifry™ is a registered trademark of SEB, France.