I owned a Blofeld desktop for a period of time. I bought it used, got a decent deal on it, but later sold it...perhaps a bit prematurely. I sold it in favor of not having redundancy next to the Q, which I kept...and Largo.
Here's my take on the Blofeld, if it helps you any -- PRO's and CON's:
PROS:
1. The keyboard version, though I've never touched one, is reported to have a great, high-quality keybed.
2. Sound is unique, the Waldorf way. It is versatile.
3. You can upgrade/unlock the Blofeld to allow user samples to be uploaded and also get new sample-based waveforms to use. This can create more dynamic patches.
4. Good, graphic LCD screen.
5. USB interface. Some freebie patch editors are available.
CONS:
1. Waldorf synths seem to have very quiet outputs. The Blofeld is no exception.
2. Time-based FX can only exist once. This means you can't have a delay and a reverb in the same patch.
3. Limited knobs. You must get used to menu diving.
4. Polyphony gets hammered to next-to-nothing if a comb filter is used plus FX.
5. USB connection can create an annoying ground-loop and hum.
6. No unison.
7. No sub-oscillators.
8. Largo.
Con #8 is quite important, and also owning Largo further bolstered my liquidation of the Blofeld. Largo, IMO, sounded (and continues to sound) awesome...much better than the Blofeld. Blofeld sounded "tinny" and fragile. Largo can sound rich and full. Largo also has 256 voices of polyphony. And if you run out, then simply load another instance of it. On the other hand, Largo does not have the comb filter or the PPG filter, but I'm not sure if Blofeld has the latter anyway.
Well, that's my two cents.