You have to think of your time and money involved with keeping the fight going... I can say that if I was in your shoes, I would keep the fight going. Even if it cost me a little in the long run. If you do manage to win get a judgement against them if you can. That should make it a little easier to get your money.
I was given some great advice before we bought our first duplex. When dealing with tenants that are not paying, try making it a win, win for both. If they get behind, try working out a deal that if they leave( you avoiding court cost and the time lost) they will get a set portion or all of the security deposit back. They need to know that it depends on the shape of the property etc. Put something in writing and look over the property with them on their last day. Avoids a ton of headaches for both parties. If they would rather play hard ball, make sure you have everything in order and explain to them how much going through eviction will cost and that it will be almost impossible for them to get a place once they face eviction. Most people will make the smart choice.