Each car tyre must be mounted onto a rim. There are two common options: aluminium/light metal or steel rims. Does that really make a difference?
Weight
Let's get straight to the point. The weight is usually considered the plus point when we are talking about alloy wheels. The statement "Alloy wheels are lighter than steel rims and thus improve the driving performance" is, however, insubstantial nowadays. Of course, the main component of aluminium is a light metal, and thus, it is not as heavy as the steel that consists mostly of iron. However, the wall thicknesses of modern steel rims have become so low due to advances in technology that the difference in weight is barely noticeable. In particular, when a neat aluminium rim is combined with a large or wide tyre, the weight issue is invalid. Of course, there are exceptions: The very, very expensive alloy wheels with magnesium part (magnesium rims) and carbon rims made of carbon fibre are ultra-light, but simply too costly for private use. They are mostly used in motorsport.
Further decision criteria
Stability
The steel rim made of rolled steel is the standard equipment, especially for small cars. Steel rims often come in two parts and consist of the rim itself and wheel disc or wheel wrench. The parts are welded together so that heat and stress can't cause any damage to the seams. Alloy wheels are often poured in the piece and then painted. If the rim consists of two parts (rim well and rim base), these are screwed together. They add other metal to the rim, for example, iron, to increase the stability for those who consider aluminium as too soft. Alloy wheels are correct to call aluminium alloy rims.
Robustness
Anyone who frequently drives on unpaved roads is well advised to use steel rims. This material is much more robust than the light metal. Road salt damages the rims only visually, the structure of the steel remains unchanged. If the rim is harshly struck over the curb, it can usually be repaired relatively easily. Although steel rims rust, it affects only the surface of the rim and does not affect the driving characteristics. The rust can easily be removed. Alloy wheels, however, are much more vulnerable to grit, mud and road salt. For one thing, the moment the material gets bumped slightly, superficial scratches appear very quickly on the clear coat. If any fluid gets into these paint scratches, the rim corrodes and becomes unstable. A deep pothole can end the life of such a damaged alloy rim. The reparation of alloy wheels is a bit complicated, sometimes impossible. An alternative for alloy rims fans: Special, more robust winter alloy rims are available for an additional charge. However, these models can't (yet) compete with the stability of steel wheels at the moment.
Price
Steel rims are cheaper than aluminium ones. If you do not want to forego alloy wheels and don't have too much money at the same time, you might consider second-hand rims. When buying used alloy wheels, make sure not to buy the damaged ones. You will also need to find out if there are any superficial scratch marks. Such signs of usage are expected to appear on the used aluminium rims; it's quite common. Their absence indicates beautification work and perhaps also the concealment of defects.
Whether new or used, aluminium or steel: It's worth it to compare the prices
The look
Regarding looks, the alloy rims always look better. The lacquered, high-gloss polished or even matt brushed, sometimes with chrome parts, alloy rims are undoubtedly much prettier. Various colour options (silver, black, multicolour, car colour) make the car owner's heart beat faster. Aluminium rims can upgrade even an unspectacular family carriage and provide tuned cars with an additional eye-catcher. Not so pretty steel rims can at best be embellished with various plastic hubcap designs.
Conclusion
The choice between aluminium and steel rims is a personal choice. Both models have their pros and cons; each driver has to choose with consideration of his own priorities. Cheap and robust or pretty and a little more expensive? If you want to combine both, you can score the summer with good-looking aluminium rims and switch to the more resistant steel rims in winter.