Hi,
The main part of PCB's that I design are single face, and I have already tested autoroute in single face with Protel, Tango and Specctra: Specctra is by far the best in this scenario. Results are very good; it takes some time to converge to final solution, and normaly I can get only 2 to 4 unconnected nets that I connect manually.
Previously I place components not automatic, because I take care about crosstalk, current return path, max power of tracks, grounding, etc..
HH
NeuralC