Like you, Differin hasn't COMPLETELY cleared up my skin but knock on wood it sure does a good job. I've been on it over 2 years and if I start to get lazy about it I always break out.
You didn't say why you switched from Yasmin. If you were having problems with it you might consider Desogen. I had to make that switch and I'm pretty happy.
Spironolactone is another thing you could try.