Here is a top view of both readers as received, HZ-1050 on the left and RDM6300 on the right: D5100_01242.jpg

HZ-1050 RDM6300
Price 4.99 USD 4.62 USD
Datasheet ? Datasheet
Packaging quality Poor (ESD protective bag) OK (ESD protection + hard foam to protect headers and antenna + cardboard box)
RFID tag included Yes No
Antenna size 53x34x5mm 45x35x3mm
PCB size 62x29mm 38x18mm
PCB mounting holes Yes No
Ready to use No (headers have to be soldered) Yes
Pinout printed on PCB Yes No
Power led Yes: red, on top of PCB Yes, green, on bottom of PCB
Detection led Yes: red,on top of PCB Optional (header only)
Nominal voltage 5V 5V
Minimum operating voltage 4.2V 4.1V
Standby current (@5V) 43mA 49mA
Current while reading (@5V) 46mA 47mA
Read range 5.5cm (@5V)
4.5cm (@4.2V)
5cm (@5V)
5cm (@4.1V)
Delay between reads 800ms (during which the led stays on) 60ms (the led is on during 1ms at the end of the message)
Wiegand standard Yes: W26 or W34, jumper configurable No. Datasheet says W26 is available, but it seems it is for an alternate model, maybe the RDM630
TTL RS232 standard Yes: 9600,N,8,1 or 19200,N,8,1, jumper configurable Yes: 9600,N,8,1
RS232 format Binary:
4 data bytes (card number, blue area)
Ascii message:
STX (0x02)
2 ascii chars (version id, yellow area)
8 ascii chars (card number, blue area)
2 ascii chars (CRC)
ETX (0x03)

To illustrate the output difference, here is what you get with the same RFID tag with both readers:

HZ-1050 RS232, displayed as hex: HZ_1050_scan.png

RDM-6300 RS232, displayed as ascii (the blue trace is the led pin, blank squares are STX and ETX): RDM-6300_scan.png

As you can see, it's the same tag number, but it has to be interpreted completely differently

Hope it helps :-)