Choosing and buying a fountain or water feature
Garden design is a very personal thing, what works for one person would be wrong for another, so whether you want a large tiered design or a small pot feature its a personal thing, the only thing I would say it to enjoy whatever type you buy.
There are however some things to keep in mind that are common to all types of fountains and water features.
One thing to consider is how large the space is, this is not to say that large gardens always need large designs and small gardens need small designs but rather that fountains are an integral part of your garden design and so you need to consider how you want to incorparate them in your design, some examples would be to provide a focal point to a planting scheme, perhaps to provide a backdrop to your garden seating or barbeque area, perhaps you are close to a busy road and wish to drown out traffic noise.
If you have a large garden the temptation may be to go for a large fountain design but this very often ends up as an isolated folly sitting in the middle of an expanse of featureless lawn . Rather than go that route of trying to recreate a stately home in your 3 bed semi, perhaps consider where you spend your time, is it the little seating arrangement in the corner of your patio or is it to one side where the sun is always present late into the summer evenings. It may even be the small area in front of your french doors from where you can see the children, keep an eye on the dinner, listen for the door bell or keep one eye on your favorite TV program.
My point is really to choose a design to meet your needs rather than the formal aesthetics of a garden designer who will never spend more than a few hours in your garden, introducing water into your garden should enhance your life, not just visually as an ornament but also in the sounds of running water and the twinkle of reflected light that comes from being close to moving water. So a small fountain close to your house may well be more effective than a larger one 30m away.
Also consider what you will be doing when around your fountain or water feature, if you will be sitting, perhaps listening to the radio or reading your favorite magazines, so you may be dwarfed by the 6ft high 4 tier fountain that looked so good in the picture or the vast expanse of the garden center display area
One guideline to consider is that the larger/higher your fountain the further away it has to go from your seating area, the smaller the fountain or water feature the closer and more intimate its location, any thing above 1.5m is likely to overpower anything else around it for at least a 2m distance. If you want to drown out traffic noise a small garden fountain close to your seating area may work better than a large one which is further away, ideally place the fountain between you and the noise but as close to you as possible.
On hot summer days a fountain will cool the air around itself, if you have a prevailing direction for breezes in your garden try and position the fountain upwind of your seating or patio, this way you will benefit from its cooling affect.
Positioning a water fountain close to a window can in hot summer weather introduce a cooling breeze into your house
Next....which material is best?