I just bought a house and the same delima. Factors to take into consideration.
1. How long as the house been on the market, and have they lowered the price at all.
2. Are you going to be asking for them to pay any part of closing cost.
3. What is the cost of the house, are you talking about a 330,000 house or 150,000 house.
4. Is the house worth what they asking and you just realy like the house.
Too many unknowns.