[nabs-l] Looking for An Accessible Electronic Spanish Dictionary

[Vejas Vasiliauskas]

Hi All,
I am taking a Spanish course, and my teacher would like us to have a Spanish English dictionary but does not care which one we use.
I am considering buying either the Vox Super-Mini or the Collins Phrasebook, both of which are from IBooks. I also know that there are many apps designed specifically for this purpose. 
What did you all find most accessible?
Vejas