Although I do not practice patent and trademark litigation, I have been an attorney for almost 23 years and in my opinion this is no different than in any other legal situation. I firmly believe that it is always best to negotiate first rather than litigate first for a few reasons: 1) it is usually less expensive for all parties involved to negotiate rather than litigate as the costs associated with taking a case to even a simple one day trial can be astronomical; 2) with a negotiated settlement you usually wind up with an agreement where both parties are happy, or at least one that both parties can live with, whereas conversely with going to trial and leaving the decision up to a judge or jury can mean neither party is happy with the outcome; and 3) at least you will have the satisfaction of knowing you gave the opposing party the opportunity to avoid the astronomical fees and expenses of going to trial so you should not feel bad when they wind up having to reimburse you for your legal bills. 

So, in summary, I say negotiate first, and litigate if all attempts at an out of court resolution have been rejected and/or denied. Good luck.