What is the difference (or is there) between NY state trademark filing, and US Patent and Trademark office filing?

Super advice already given. It is so inexpensive to register in the states where you do business and with the federal Trademark Office that it makes no sense to even debate the matter. File everywhere you do business.

State registrations ARE valuable. Most states have, for example, trade name and false advertising statutes that provide broader protections than exist under federal law but, in order to sue under those statutes, the mark must be registered in the state. Also, the federal anti-dilution statute only applies to marks that are "famous" throughout the country whereas the analogous state statutes apply when the mark is "famous" within the state.

There's no downside to filing everywhere you do business --- and the cost is minimal. But have a trademark attorney do the actual filing.

You should file a Federal trademark application with the United States Patent and Trademark Office, since a New York State trademark will provide you with protection only in New York State. There are many advantages of obtainingFederal trademark protection rather than state law protection. A federally registered trademark will provide you with nationwide protection. Further, the Federal Lanham Act allows the owner of a federal trademark to seek remedies for infringement in a Federal Court. Federal trademark registration acts as prima facie evidene of (1) the validity of the mark and its registration, (2) the regristrant's ownership of the mark, and (3) the registrant's exclusive right to use the mark in commerce. Federal registration also creates "notice" (actual or constructive) and thereby allows the trademark owner to recover damages (including lost profits) for trademark infringement. State trademark protection is usually restricted to the specific products or services for which the mark has been registered, whereas the scope of protection for a federally registered trademark is usually broader. In addition, the Lanham Act provides judicial remedies that may be unavailable in state court under state common law. For eample, the Lanham Act gives the court the discretion to award treble damages against a willful infringer. The Lanham Act also allows a court to impose attorneys fees against the accused infringer in certain types of exceptional cases. Further, after five years a federal trademark becomes "incontestable" (following filing of an affidavit of incontestability with the United States Patent Office). Once this affidavit is filed, the federal trademark can be challenged as invalid only if it has (a) become generic, (b) been abandoned, (c) was obtained through fraud, or (d) was deceptive, scandalous or disparaged or brought into disrepute a person, institution, belief or national symbol. Thus, I would advise clients to first apply for federal trademark protection.

This is not to say that it is never worthwhile to seek state trademark protection. But state registration provides far more limited protection and generally takes a back-seat to federal registration.

A federal trademark gives you rights in the U.S., not the world. A state mark give you rights in the state, not the U.S. Basically, it's a race for geographical rights, and generally trademark users are rewarded for both their actual use, and their registrations. If you're using the mark on the internet or in other states, then you should file for a federal trademark registration. State registration is usually somewhat faster and cheaper, but state law covers less. If you can afford both, get both, but if you can only afford one, get the federal one. Hire an IP lawyer to help you, because you want to get it right the first time and there are lots of ways to screw up a TM application.

What you want to do is claim rights to your mark where you can show a likelihood of entry into an area where a local junior (subsequent) user exists. The junior user may continue to use the mark in the state for as long as the federal registrant remains outside the market area, but once the federal registrant shows a likelihood of entry, the junior user has to stop using the mark. A federal registration is constructive notice that the registrant has the right to use the mark throughout the entire country (even if the registrant is not using it in a specific geographic area) and can prevent others from using the same or similar mark anywhere in the U.S.

But there's an exception to this when the state mark registered prior to the federal one. If the state mark was in use before the date of first use of the federally registered mark, the prior state user may have some rights to use the mark, but those rights would be limited to a certain geographical area, usually the state where the mark has been registered and used. A state registration may also be helpful as a means of establishing prior use of a mark.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.