I own a WP7 running Mango, It's a pretty decent device, which is fairly easy to use (i came from IOS). However, it's still a new OS with a few glaring omissions (no way to backup for example) and a not very full app-store. To answer your questions:
- Wifi works fine, though it switches off when you lock the phone. No you cant change this.
Getting pics off the phone is done by syncing with Zune via USB or over wifi. Bluetooth file transfers are not supported in the OS, so forget BT.
My girlfriend can use the phone fine and she's extremely non-techy. However, she finds the IPhone easier to use.