This is what Hardkernel shows on their page for the Odroid-C2:
ODROID-C2 ODROID-C1+ RPi 3 Model B
CPU Amlogic S905 SoC
4 x ARM Cortex-A53 1.5GHz
64bit ARMv8 Architecture @28nm
Amlogic S805 SoC
4 x ARM Cortex-A5 1.5GHz
32bit ARMv7 Architecture @28nm
Broadcom BCM2837
4 x ARM Cortex-A53 1.2Ghz
64bit ARMv7 Architecture @40nm
GPU 3 x ARM Mali-450 MP 700MHz 2 x ARM Mali-450 MP 600MHz 1 x VideoCore IV 250MHz
RAM 2GB 32bit DDR3 912MHz 1GB 32bit DDR3 792MHz 1GB 32bit LPDDR2 450MHz
Flash Storage Micro-SD UHS-1 @83Mhz/SDR50 or
eMMC5.0 storage option
Micro-SD UHS-1 @78Mhz/SDR50 or
eMMC4.5 storage option
Micro-SD @ 50Mhz/SDR25
No eMMC storage option
USB2.0 Host 4 Ports 4 Ports 4 Ports
USB2.0 Device
OTG
1 Port for Linux USB Gadget device or
USB host
1 Port for Linux USB Gadget device or
USB host
No
Ethernet / LAN 10 / 100 / 1000 Mbit/s 10 / 100 / 1000 Mbit/s 10 / 100 Mbit/s
Video Output HDMI 2.0 4K / 60Hz HDMI 1.4 HDMI 1.4 / RCA / DSI
Audio Output HDMI / I2S HDMI / I2S MDMI / 3.5mm Jack / I2S
Camera Input USB 720p USB 720p MIPI CSI 1080p
Real Time Clock No (unless using an add-on module) Yes (on-board RTC) No (unless using an add-on module)
IR Receiver Yes (on-board IR sensor) Yes (on-board IR sensor) No (unless using an add-on module)
IO Expansion 40 + 7 pin port
GPIO / UART / I2C / I2S / ADC
40 + 7 pin port
GPIO / UART / SPI / I2C / I2S / ADC
40 pin port
GPIO / UART / SPI / I2S
ADC 10bit SAR 2 channels 10bit SAR 2 channels No (unless using an add-on board)
Heat sink Included Included Optional
Size 85 x 56 mm (3.35 x 2.2 inch) 85 x 56 mm (3.35 x 2.2 inch) 85 x 56 mm (3.35 x 2.2 inch)
Weight 40g (1.41oz) 40g (1.41oz) 42g (1.48oz)
Price $46 $35 $35
Nice, making the Odroid-C2 really shine, but is it right? No, this is made by a shrewd marketeer, who does not stay away from making some bad comparisons and/or downright altering the facts about CPU and the GPU:

CPU: The C2 is presented as having a 64bit ARMv8 Architecture, while the Raspberry Pi 3 is presented as having 64bit ARMv7 Architecture. That is not true, both have 64bit ARMv8 Architecture. It is just that the operating systems that are used for both the Raspberry and the Odroid are often completely 32-bits, or only have a 64-bit kernel with a 32-bit userland (e.g. the 64-bit Android that the Odroid-C2 runs has a 32-bit userland).

GPU: The C2 is presented as having a triple-core ARM Mali-450 MP@700MHz, while the Raspberry Pi 3 is presented as having a single core VideoCore IV@250MHz. That is not true, the value given for the Raspberry Pi 3 is that of the original Raspberry Pi 1. In fact the Raspberry Pi 3 has a quad-core VideoCore IV, with the 3D part of the GPU @300 MHz and the video part of the GPU @400 MHz.

Price: I have yet to see a Odroid-C2 for less than 60 Euro's -more often they are at 85-90 Euro's, which is around 100 US$.