Hey _Drizzy_,
Thanks for the question. Do you have MMS Messaging enabled on your iPhone? If not, that would explain why you are unable to receive videos from others, but able to receive them via iMessage.
iOS: Troubleshooting Messages
http://support.apple.com/kb/TS2755
If you still can't send or receive MMS messages
1. To send and receive MMS messages on your iPhone, verify that your wireless carrier supports MMS.
2. Ensure that MMS Messaging is turned on in Settings > Messages.
3. Verify that your phone is able to access cellular data.
- Some carriers allow you to edit your APN (Access Point Name), which may prevent MMS from working.
- If you are roaming outside your calling area, make sure you have Data Roaming turned on in Settings > General > Cellular to send or receive MMS content.
- While on a phone call, you will be unable to send or receive MMS messages when using an EDGE, GPRS, or any CDMA cellular data network. After the phone call ends, you will receive any incoming messages. If you tried to send an MMS message, you may need to send it again.
4. If the issue persists and your wireless carrier has confirmed that your wireless account is provisioned2 for MMS, restore the iPhone.
Thanks,
Matt M.