Are all VCOs created equal?

From a beginners POV just wondering if there is a difference is sound quality (I.e. depth, timbre, resonance) between VCO modules? I gather they all sweep through the audible frequency range in some form or other, but is there a definable quality that makes one more pleasing than another? I am thinking about picking up a Lifeforms module to start my synth module journey and wondering if the VCOs in the unit are any better or worse than others. Cheers.

They are all different, due to their differing circuits and components. However it's very subjective to what makes them pleasing to someone. What makes them differ is their individual features, eg. FM (linear, Exp), PWM, Sync (various types), wavefolding, Sub OSC, number of different waveforms, etc. Then you have digital oscillators, they can sound like anything.

To broadly generalize - there are versatile bread 'n butter synths oscillators that output the typical sine, tri, saw, sqr - eg: Doepfer A-110, Tiptop 3000, Intellijel Dixie etc. Saw-core or tri-core implementations will generate slightly different wave shapes (visible on an oscillator) and sound slightly different. On the other end of the spectrum there's the specialty ones that use custom wavetables or specific sound generation algorithms to evoke a singular personality e.g. The Harvestman Piston Honda or Donut, Noise Engineering Loquelic Iteratus, Make Noise Telharmonic. Of course there are also modules somewhere in the middle - familiar wave outputs, but some extra functionality or features: Synthesis Technology`s E 350, Make Noise DPO etc.

I highly recommend reviewing as many videos & sound demos as you can to get a feel for sound & functionality and in particular would recommend visiting a specialty modular store (even if a trip is required) to try the stuff in person.

Do not panic about making exactly the right choice - it may not be clear what you will eventually settle down with until you acquire some experience with modular - and there is a great market for used gear so it is pretty easy to trade towards what will eventually become part of your own personalized instrument.

EDITED May 2nd 2016, 19:50

Not better or worse, but they all do sound different, even within the same category. That's why there are so many out there! And many have different functionality too, as people have said.

People really love the Dixie ii+ for example (as do I).

Complex oscillators and digital ones sound quite different, too. Check out a demo of the Loquelic Iteritas! Or Braids!