Peepod naps - Has anyone got any advice?

Hi - am 20 weeks preg with first baby, and sussing out baby gear.  I have been considering using the Peapod washable nappies.  I don't really know much about them - have only seen them in the stores and had someone at work recommend them.  I would like to save some money and reduce my environmental impact.  Is this the way to go?

I have enough disposable naps stored up for the "explosive" newborn stage, so if I was to introduce Peapods it would be from the infant stage onwards, and probably only for daytime use. 

Are there any experienced mums with opinions on these nappies, and also how many would I need to buy?  (if I use them for daytime use, and do a wash say every 1-2 days?)

Thanks - I didn't realise it existed.  Will go for a looksee. : )