I would definitely purchase the Nokia Lumia 520.
Whilst the Lumia doesn't have as many apps as Android and iOS, it makes up for it with Facebook, Twitter, Xbox, Office and Skype built in. There's also Nokia Music for completely free and unlimited music mixes, and the world's best maps. The home screen makes it easy to organise all your favourite people, apps and information.
The Lumia 520 runs Windows Phone 8 - which supports Bluetooth File Transfer for pictures, audio, contact information and Microsoft Office documents.
It is vastly superior to the Samsung Galaxy Ace and iPhone 3GS in specifications. It has a larger, higher resolution, more responsive touchscreen; HD video recording, superior battery life, smoother and faster operation, and a much more newer OS .