Contract jurisdiction venue

Why do they do this? Two common reasons: (1) New York's contract law is very well-defined and understood, much like Delaware's corporations law. But, every states's contract laws are fairly well defined, so this isn't really a huge advantage. (2) They want to apply some sort of "neutral" law. (This (2) doesn't really make any sense -- you want neutral judges, not neutral law. But, that's what some people do.)

Does it create any new liabilities? It shouldn't open you up to any new taxes. It might somewhat change how the contract is interpreted or how parts of it are enforced -- there is some variation between states. In North Carolina, for example, most provisions that say "The loser pays the winner's attorneys fees" aren't enforced when they might be under New York law.

NOW.... There's an entirely separate question whether this provision can actually be enforced (Ditto for the related choice-of-forum provision that says "Oh, and we're going to use New York courts to settle our disputes"). As a general rule, the further away these provisions get from a connection to the contract or the parties, the less likely they are to be enforced. Sure, a New York judge might say "I'll enforce this as written" but if you sue them in Ohio, the Ohio judge may not send it to New York.

While I agree with most of Chris's answer, I have a slightly different perspective:

The reason for the change is precisely because NY law is neutral (neither A nor B), not to mention well-known and well-respected. As a result, the choice-of-law issue disappears - neither party wins, and neither loses on this negotiation point. In other words, the other party is removing this issue in an effort to reach agreement.

Don't spend time or money worrying about unintended side effects / liabilities - you probably cannot readily determine whether they exist or what they are at this time, or which party they would favor, and they probably are not material, in any event.

The issue you didn't mention is whether there is a forum-selection clause - i.e., whether the parties agree to (perhaps exclusive) jurisdiction and venue in A or B. That's the provision that gives one party a noticeable tactical advantage if litigation occurs.

Disclaimer: This information does not constitute legal advice and does not establish an attorney-client relationship.