two airfields to choose
I definitely prefer Bembridge I have to say... both are decent, and I have heard that Sandown has a new restaurant... but Bembridge is certainly very good in terms of service, and closer to a more interesting town (my wife and kids were very unimpressed with Sandown vs. Bembridge town).
Note however that the x-wind can be a fairly stiff at either - why not decide on the day based on which is most favourable (they're almost at 90 degress to each other, so one of them should be ok!)...
Andy