Taxes are the same no matter what you buy. Property is reassessed upon sale and SF Tax Assessor indicates new taxes will be approximately 1.141% of the new purchase price today.
Transfer taxes are also paid by all Sellers upon completion of a sale (at various levels depending on the sale price.) Developers of new construction usually ask the Buyer pay those taxes. You can, however, negotiate with the Seller to ask him to pay or to split with you....... and sometimes you will be successful.
Please contact me if you have any more questions or want further information on the transfer tax levels.
Hope this helps.