iMAN i8800 and DG1 are listed on Vifocal,and owns different advantages.Meanwhile,they shares some similarities.The following report will provide some contrast between them.

Model DG1 :http://vifocal.com/dg1-smartphone-ip68-quad-core-android-4-2-os-4-0-inch-screen.html

Band 2G: GSM 850/900/1800/1900MHz
3G: WCDMA 850/2100MHz
Sim Card Dual SIM Card Dual Standby(one Micro SIM card )
Service Provide Unlocked
Style Bar
Color Black&Yellow
Shell Material Plastic

System
OS Android 4.2
CPU MTK6582, Cortex A7 Quad core, 1.3Ghz
GPU: Mali-400
ROM 8GB
RAM 1GB

Screen
Display Size 4.0 Inch
Type IPS, capacitive touch screen
Resolution 800 x 480 pixels

Camera/Picture Resolution Dual Cameras, 5.0MP front camera, 8.0MP back camera with flashlight and auto focus,
support HDR, panorama

Basic Information
Model iMAN i8800:http://vifocal.com/iman-i8800-smartphone-ip68-quad-core-android-4-4-os-5-5-inch-hd-screen.html

Band 2G: GSM 850/900/1800/1900MHz
3G: WCDMA 850/2100MHz
Sim Card Dual SIM Card Dual Standby(one Micro SIM card )
Service Provide Unlocked
Style Bar
Color Black&Yellow
Shell Material Plastic

System
OS Android 4.4
CPU Qualcomm MSM8916, Cortex A7 quad core, 1.2GHz;
GPU: Adreno306
ROM 8GB
RAM 1GB

Screen
Display Size 5.5 Inch
Type IPS, capacitive touch screen
Resolution 1280 x 720 pixels

Camera/Picture Resolution Dual Cameras, 5.0MP front camera, 13.0MP back camera with flashlight and auto focus,
support HDR, panorama