Here's a quick & lazy review with no photos.
Price & shipping
I bought the GBxCart RW v1.3 (Micro-USB) for 29 USD + 4.5 USD international shipping. Shipped from Australia in a padded envelope with the device sealed inside an anti-static baggy. That's OK but I was afraid of damage, since it's a small padded envelope with no cardboard support, and the device is easy to damage by weight or bending. Anyway, it was fine when received.
Product overview
It's a small board with a red "initialisation" LED that turns on for a moment when the USB is connected to a PC. Then, by default the green LED of the GBA 3.3V turns on. The board is thick and looks nice, and the Micro-USB plug is tight with my cable (I use an old Kindle cable). The cartridge connectors are tight enough but you may have to plug and unplug a few times until the program reads it correctly. Basically it's like inserting a game inside a console... you know how that is... need to try a few times, clean the connectors, blow on them and try again until it works.
The board has NO casing and there's no option to buy one, so it needs to be handled and stored with care. Would be amazing to have casings available in the future.
Software
The GUI is super simple and includes COM port drivers. Upon connection the board for the first time, you will have to install the drivers manually, which takes a second if you know how to do that from the device manager in Windows. Works great with my Windows 7 x64 configuration.
So you open the GUI, plug a cartridge and connect the USB cable. The green LED is for 3.3V GBA carts, so you will have to click on "GB" in the GUI to select GB/GBC, then press "CONNECT". This will wake up the board and change the LED to red for 5.5 GB/GBC carts.
Now you have to press "READ CART INFO" and make sure that all the specs in the text box are found correctly. If this is not the case, you MUST press "DISCONNECT", remove one end of the USB cable, insert again, and try the process again until it works. That's what the manual says. You don't want to risk damaging your precious GB game right?
If the cart reads correctly, it will show something like this:
Game title: SUPER MARIOLAND
MBC type: MBC1
ROM size: 64KByte (4 banks)
RAM size: None
Header Checksum: OK
If the HEADER CHECKSUM is OK, you can now backup the ROM by pressing READ ROM. You can specify a default folder for ROM file in the GUI.
The GUI allows you to backup game saves, restore game saves, write to flash carts and dump from flash carts. These are function I don't need at the moment, so I haven't tried them.
I dumped 2 Super Mario Land carts which use different ROM types (one is a proper ROM, one is a glop-top). Took several tries to have them read properly, but once it was successful, the dump process worked on first try and the .gb files created worked great with Visual Boy Advance 1.8.0.
What I don't like
I have a single complaint, it's that previous hardware revisions of the product had a physical switch for 3.3/5V, while the latest revision only has coloured LED (green/red), so you must select the voltage in the GUI. It always defaults to GBA so that's a bit annoying, you gotta remember to click GB and then read the cartridge. I believe it saves the developer a few cents to remove the physical switch.
Conclusion
So far it's a great purchase, and does exactly what I wanted it to do. Now, the big question is, are the dumped .gb files exactly perfectly byte per byte the same as the ROM? I can't tell, but I downloaded a few ROM of Super Mario Land from random rom websites, and ran md5checker. They all reported the same checksum as my 2 dumps. Looks good!