Which is better a small claims case or mechanics lein

The two are not mutually inconsistent.  As a painter, you may have a right to a statutory lien, but I am not sure of Illinois law in this regard (I think it would be an artisan't lien, not a mechanic's lien).  If there is no statute giving you the right to assert a lien, and you have no contract giving you that right, you can only assert a lien after you obtain a judgment in a law suit.  At any rate, the lien only gives you a security interest, it doesn't get paid until you either foreclose on it in a lawsuit or the homeowner decides to satisfy it, usually when they sell the home.  In contrast, if you win and obtain a judgment in a lawsuit, you will not only have a judgment lien on the house (assuming that Illinois works the same way as NY), you will be able to use various collection mechanisms to help you collect on your judgment.