A general warranty seller warrants (promises or guarantees) that he holds clear title to the property and has a right to sell it. This warranty covers (all) problems created back in the chain of title. A special warranty seller, however, basically only promises or guarantees that he has not created a title problem. Obviously then general warranty is better than special warranty.
If you are a listing agent there is no need to strike the boilerplate REIN language unless you represent a fiduciary (executor, trustee, etc.) or perhaps an institutional seller.
If you are a buyer’s agent protect your buyer by recommending (insisting really) that he purchase an enhanced owner’s title policy. I would question why a non-institutional seller would want to convey by special warranty and that ought to raise a red flag.
Never accept a deal where the seller strikes the clear, marketable and insurable title language of the contract, and I would prefer that you let me review any contracts where the mechanic’s lien or seller affidavit language is struck.
Feel free to contact me if you have questions or concerns.