I looked at this and asked myself "who's going to sue a sterling fellow like me anyway?" I opted for the $5000 deductible. I work with companies that have a fairly realistic understanding of what I'm promising. If I was a Structural guy doing residential, I might have reached a different conclusion. I think you need to look really hard at the potential to be sued. While the savings THIS YEAR on $5000 deductible over first-dollar insurance would take 10 years to recover, next year the special deal may be over and the first-dollar stuff might be twice as much as the deductible.
I went to a class on this a few years ago (part of my "ethics" PDH requirement) and found something interesting. When you stop paying for insurance, it stops covering you (not a major revelation). Also, when you start insurance it covers you from the date it is bound until it is cancelled (again, in itself not a major revelation). The important fact is that if you change carriers (and in many cases if you change coverage) then unless you purchase explicit coverage for the prior period YOU ARE NOT INSURED for the times covered by the old policies. So if you change policies in June (without paying terrible fees for a "bridge" policy) and someone finds that something you did in May is actionable, then the whole thing is on you and neither your old carrier nor your new carrier will talk to you (except that your new carrier my cancel your new policy). The way the instructor explained it, if you change your deductible, unless you are very careful to make it a modification (with the same policy number) instead of a new policy, you can easily find yourself uninsured for recent activities. Since I've been with the same carrier, same deductible, and same policy number from day 1, any activities that my company might have been liable for from inception are covered. I don't shop for better rates on my insurance since the bridge policies are horribly expensive.
David