Looking for SERIAL/USERT RFID Reader/Writer. (feedback requested)

A while back (years ago) I got an RFID reader/writer.

However I quickly got discouraged not being able to figure out how to write to the card and could only read a cards 'id' and then use it (hard coded) in any sketch..

This is the one I got: http://www.ebay.com/itm/RFID-module-Kit-13-56-Mhz-with-Tags-SPI-Write-and-Read-For-Arduino-/200892882864?pt=UK_Sound_Vision_Other&hash=item2ec6261fb0

I think I even posted a thread on it.. but this was the only one I could find: https://forum.arduino.cc/index.php?topic=89700.0

documentation was insanely painful if I recall.

I DO NOT WANT AN SPI BASED ONE!

I want a SERIAL/UART, 13.56MHz, reader/writer based one. Preferably cheaper and small in nature.

My thought process is that getting a serial based one will be easier to understand documentation and be able to actually READ & WRITE to the cards themselves.. using them for allowance cards.. or laundry cards...etc something that can be updated dynamically when read...etc

So my question is.. what SERIAL/UART based RFID reader/writers have you guys used? Pros? Cons? on your specific model/project?

Libraries available/used with your hardware?

I looked on ebay, ... found some that look promising. But to be honest.. when I read the descriptions..

they mention all protocols.. SERIAL, SPI, I2C

ie: http://www.ebay.com/itm/13-56Mhz-Reader-RFID-Wireless-Module-UART-TTL-Support-Mifare-RC522-S50-S70-/331280146888?hash=item4d21d5e1c8:g:QAgAAOSwxH1T30j6

so maybe a physical setting on the board? (I always question things like this)

All communication/feedback/suggestions are appreciated.

thanks!

*bump..

anyone use a SERIAL/UART RFID reader/writer they wanna talk about?