Thanks for all the replies. Some very good advice.
To answer the questions, I am not currently working under any contract, but would have one at the new place, which I and my lawyer have reviewed.
To elaborate on my current position I was hired 15 yrs ago, and about 10 yrs ago we made a handshake agreement where I would be paid a certain percentage of the companies gross revenue, in addition to a small base salary. Well that worked great up until this year when the boss decided I was making too much. He essentially went back on our deal and said he could not pay me the percentage anymore. Now granted the company is bringing in a lot more than what it was back when we made the agreement but I am solely responsible for building it up to what it is now. I make more dollars than I did in the past,but less percentage, and more work on my part.
When my employer made these changes I was very unhappy. I told them I wanted to be parterns, wanted our original deal, etc and he would not budge. In his mind he honestly thinks I make too much as it is, even though I make a lot of money for him.
The prospective employer is our competitor. They know what I can do. They are a solid company, been around since the 80's. If I join them I am sure some of my clients will follow, but not all, and it does not really matter as they have plenty of their own.
Anyway all this aside I just want to handle it the right way.