In spirit, all home sous vide machines fundamentally do the same thing. They maintain a water bath at a very precise temperature, allowing you to cook food to exactly the temperature you want it to be. But since there are many ways of going about heating water, the devices can be radically different in design, each with their upsides and downsides.
I've had a SousVide Supreme for almost 2 years now and while it's a fantastic machine, there have been a bunch of new entries onto the home sous vide scene during that time. When Anova contacted me and asked if I'd be interested in reviewing a unit I jumped at the chance because it uses a design similar to the $800 Polyscience immersion circulator, which I use for work.
Like the Polyscience unit, the Anova is an immersion circulator, with a heating element and a pump that circulates the water to ensure a consistent temperature. The design also makes it compact because it doesn't include a vessel to hold the water. This means you can use it with almost any container that's heat-safe, such as pots, buckets, or even ice chests. The pump keeps water circulating around whatever vessel you chose and it can be used to circulate up to 22 liters (5.8 gallons) of water. The touch screen and minimalist interface makes it ridiculously easy and the cover for the heating element is easily removed so you can clean it if you have a bag rupture.
The SousVide Supreme on the other hand works by silently heating an insulated water-bath. Aside from being very quiet, it uses less power because there is no pump to run and the insulated vessel retains heat better. Because the unit has a lid, you can keep it running for days without having to replenish water lost due to evaporation. The downsides are that the size of the bath is limited (11 liters), and you tend to get temperature fluctuations in different parts of the bath because the convection currents which move the water around get disrupted by the food. The unit is also pretty large, making it a pain to store in a small apartment.
So which one is better? Well, to be honest, both. The Anova, is easier to setup, heats up faster, and maintains a more consistent water temperature so I found myself using it for quick things like seafood, chicken, steaks and eggs. But for longer jobs such as for ribs, shanks, and other tough cuts of meat, I still prefered the SousVide Supreme because it runs silently, doesn't have an evaporation problem, and uses less power.
That said, if I had to chose just one, the Anova at $199, is less than half the price of the SousVide Supreme and performs just as well (if not better) for most applications.
I haven't tested the [Nomiku or Sansaire, but there's already a great comparisson over at Serious Eats. As for the Codlo, I don't have an analog rice cooker or crock pot, so it's it's not a practical solution for me, and at 99GBP ($165 USD), it's a lot of money for a device that doesn't come with a heating element or a pump.