I didn't realize that Renderosity is making strict rules on the products, now. Though they are well on their way to killing the forum community here. Oh, I forgot a very important and very negative difference about DAZ-- they don't allow off-site products in promo images, nor add-ons for off-site products to be sold in their store. I can't remember if Hivewire3D is the same way or not (bear in mind that Hivewire3D is a split-off from DAZ3D, so products from one store can be found in the other) Neither RDNA nor Rendo have such a rule. So the lineup of cons goes like this:

DAZ: Strict guidelines for products (must have metadata, many products rejected, etc.), super-strict forum TOS, no add-ons for off-site products, no off-site products in promo renders, Daz takes 50% of net vendor revenue-- more for non-exclusive products.

RDNA: Requires vendors to make products exclusive-only with few exceptions (generally software, scripts, and plug-ins) I can't remember how much net vendor revenue they take, but it seems like it was lower than 50%.

HIVEWIRE3D: Not sure, but might share Daz's off-site promo render and product add-ons ban (excepting DAZ products) Very limited selection of non-Dawn/Dusk/Luna products

CONTENT PARADISE: Dying. No forums, no email/on-site tech support (only phone#, which I'm not sure even works), no way for someone to become a new vendor. Product release date changes whenever said product is updated, creating the illusion that CP mostly sells low-quality products.

The main disadvantage to Renderosity is that, like DAZ, they take 50% of net vendor revenue.