The DRMd books on fictionwise appear to come in 4 formats ...
- Secure Microsoft Reader Format - I realise many people think this is the best, but I'm on a Mac, without windows, so this format isn't an option as far as I am aware.

- Secure Adobe Format - I believe they use secure PDF rather than ePUB for this, so probably not a sensible choice, as I don't think it can easily be un-DRMd and converted for the Sony.

- Secure Mobipocket Format - This is currently my format of choice as I can un-DRM it and convert to ePUB for my PRS-505.

- Secure eReader Format - Currently an unknown quantity .. I believe I can remove the DRM and convert these to ePUB/LRF, but I have to register my credit card with fictionwise and I'm currently just using paypal and micropay.

Are there any advantages to the eReader format over the Mobipocket format, I can't really find much info about how they compare. I don't really want to buy lots of Mobis only to find it isn't the best option.
Advice please.