2210 or 4150

Hi can you help. Which is better 2210 or 4150 ?. I do not need wi fi but like the look of 4150 better .Would dual slots on 2210 be more usefull to me? its also cheaper. Whats the difference between SD & SDIO ?.
PS this will be my first pda. Thanks

[Charlie]

Welcome to our forums.
They both offer different features. To be honest only you can say if dual slots will be of more use to you. SD is just a memory standard whereas SDIO is an input/output interface meaning you can you devices other then just memory cards.