Quite a few assertions going on in this thread and some of them are pretty way off the mark!
Many modern 'synthesisers' are not really synthesisers, they are essentially sample playback devices with manipulation modules such as Ocsillators, Filters and Envelope Generators. A true synthesiser, by definition, produces sounds with a predictable and limited set of dynamic ranges and harmonic content. The playback based synths are based on processed audio files which are usually very limited in their dynamic range and timbre. Sure you can dial down the volume of a synth during mixing to give a wide dynamic range but an acoustic instrument will actually produce a constantly varying harmonic content at every different volume. Remember, synths and samplers are MIDI devices which have an absolute maximum of 128 varying steps of velocity, volume (and therefore timbre) whereas for an acoustic intrument these limitations are virtually infinite in comparison. So in conclusion, electronica is far more simplistic in it's range of timbre and dynamics than say orchestral music.
However, the production is far more important than the genre. I would rather listen to a really well produced piece of electronica than a poorly produced orchestral performance. Skill of the engineer and producer and quality of equipment (for recording/production) is what is important.
Comparing live genres such as classical and jazz against rock and pop is a pointless exercise at an aesthetic level. Classical music for example is all about the live performace and the engineer and producer have to do the best they can to capture this performance on a recording. Most rock and pretty much all pop (inc sub genres like hip-hop, electronica, dance, etc) on the other hand are genres whose evolution has been driven by recording technology. Recordings are created by the producer and then if a live performance is required some method of performance has to be devised (or faked) because much of what you hear on the recording is only possible in the studio. The philosophy of performance/recording for these genres is completely opposite to the philosophy of the jazz or classical recording.
As a generalisation, some genres are more 'high quality' from a purely technical audio quality than others. Hip-hop for example is often very poorly recorded and produced because it has been created by people without the quality of equipment or exeperience. However, I have heard some well recorded and produced hip-hop. The same is often true for electronica and dance, which can be produced by a kid in a bedroom with a PC and a sound card. A kid in a bedroom will not be able to record a live symphony orchestra, this will usually be the exclusive pervue of a professional and highly experienced recording and production team with hundreds of thousands of dollars worth of equipment. So, for technical audio quality the comparison between these genres is generally going to be pretty easy.