Well speaking from experience there is no protection at all offered to the small guy. People like Son'y, Siemens and loads of others just ignore the patent because they know that you cannot go after them and even if you do they can delay any action until way past your demise for very little money and from the other side they patent everything even things that have prior art like the Stratasys offerings and again the burden of proof is not on them but on whoever wishes to challenge it.

The whole system is wrong and the only way to invent and profit is to be first to product.

Defending a patent is tedious and the outcome is down to individual people who know naff all about the subject in question, the only people that profit are lawyers. I have done this against Siemens and won but it made no difference, they carried on anyway.