I would advise against that, I tried to dabble with both platforms, but the markup at which those shares are sold is often incredibly high: common shares of most companies on those platforms are actually sold at prices higher than the preferred (crazy), even if such company just went through a very recent round of funding, meaning that the preferred price is pretty much the very top investors valued the company at.

I honestly don't know who would buy that, the idea I got by doing some basic due diligence on those deals is that who puts them online thinks "let's see if we can attract some dumb money to give us some liquidity at an insane premium". If you sell things at a fair price (e.g. selling common shares at the preferred price * 0.8, depending on the current stage of the company), investors will want to give you liquidity way before your offer on equityzen gets accepted and pollutes the cap table (I speak from direct experience), so what's left on those crowdsourced platforms is many times overpriced garbage.