I have an LG top loader as well - sorry can't think of model (I'm at work) but its 6kg. I'd recommend a larger one if you can. It does have an agitator and I wash nappies on the 'gentle cycle' and never had any problems. It also has a prewash cycle which is great.

We've had it for 4 years and never had an issue. I'm thinking of upgrading to a bigger one in the next year or two and I'm considering a bigger LG!