A mixer showers is pretty much what is says, it mixes hot and cold water to the exact temperature that you want. Well, that's what it's supposed to do. A cheap mixer shower can do this just as well as an expensive mixer shower, albeit, without as many features or looking as good. But a cheap mixer shower can also leave you feeling hot and cold, literally. Go too low on the price and you'll end up with nothing but frustration and the extra £100 for a better mixer shower will now seem like a bargain
Most of the modern mixer showers are pretty good now. Even the cheap mixer showers can keep the correct temperature if they've got a decent heating system behind them. Some of the more expensive ones can work pretty well even if your heating systems is a little outdated. They can even be good enough on low pressure heating systems too.
One of the main benefits to a mixer shower is that it is run directly from your heating system. This is usually cheaper than an electric shower, but this is dependant on the type of heating system that you've got. A basic cheap mixer shower from Mira for example will require no electrical wiring to get it working. If you've already got an old mixer shower and are replacing it like for like, then this is also a pretty simple job if you're fairly handy, or a cheap job to get a plumber in to do.
As well as being cheaper to run, they can be easier to use to. Often being just one lever turned to the desired temperature and you're good to go, plus if the event of a power cut, you've still got a hot shower. The downside of this is that if your boiler packs up you've no shower. But you can't have it both ways I guess.
Types of Mixer Shower
Single lever mixer showers Pretty straight forward, a single lever controls the flow of water as well as the temp. Very easy to use.
Sequential mixer showers This has just one lever, the more the lever is turned the hotter the water gets. You can not control the flow of water with this type of shower.
Concentric mixer showers 2 separate controls, or knobs, one for the flow and one for the temp. Good thing about this is once you've got the correct temp, you never need to touch it if
you're the only one using the shower.