There are varying viscosities of liquid cements available, some very thin, some slightly thicker.
The very thin types eg. Testors "pink", Tamiya extra-thin etc work by chemically "welding" the parts together. In effect they work by slightly melting the mating surfaces and allowing them to re-harden.
The slightly thicker types (sometimes in a jar with a brush, sometimes in a squeeze bottle with a needle-point applicator tip) work partially by chemical action as described above, but also contain an amount of plastic "resin" for additional strength.
If you are switching from a tube cement to a thin liquid type, you will need to learn to adjust to the different properties of the cement. If you have been accustomed to applying cement to one part and then putting it in place, this will not necessarily work with a thin liquid cement. If you apply to one part and then try to position it, you may well find that the glue will have all but evaporated before you get the part into position. Though they can be used for smaller assemblies, the thin liquid types are best suited for jobs where there are long uninterrupted mating surfaces, Hold the parts together and apply the cement to the join. The closeness of the seam and the low viscosity of the cement will cause the cement to flow along the join by capillary action. This ability of the cement to flow so easily means that you can sometimes get yourself in trouble very easily. The cement will flow just as easily down crevices, panel lines or even between your fingers and the surface of your model (leaving nasty permanently etched fingerprints) - always do a "finger check" before applying liquid cement.
The thicker type of liquid cement will afford you a little more working time compared to the thin type, while still being much cleaner than the traditional tube types. Generally these are applied by brush or the aforementioned needle-tip applicator and tend to stay where they're applied.
If you want to use CA/Superglue, you can also do so, usually without any ill effects on the styrene. However, when using CA glues, remember that the downside is that you usually only get one shot at getting it right. While CA glues can be used for general assembly, they are most often used when joining dissimilar materials, eg. photoetched brass to styrene.
There are glues/cements for different applications - it's just a matter of learning which type works best for the immediate task at hand. 