Look here: How do the the professionals/experts think of FVDI, FVDI2, VVDI2?
Part 1: fvdi vs fvdi2
FVDI 2015: has the same interface as the original AVDI
FVDI2 2018: includes FVDI, FLY OBD Terminator, J2534 software and VVDI2
Note that, This 2018 version has the same software versions as the 2015 version except that has updated software for VAG and BMW/Mini which is from the VVDI software. IMMO 4 and 5 key programming is working.
FVDI2: is able to do diagnosis, add new keys and program ECUs….(it’s said that it can do everything for car repair, but in the real tests, you need luck with it coz its stability is not really good.)
VVDI2: is known as an auto key programmer, esp. for VAG (4th & 5th immo, MQB) and BMW (EWS, CAS, FEM/BDC)! Actually, if you know Xhorse well, you will use vvdi tools for key programming instead of diagnostics, odometer correction, etc… although functions expect key adding can be done but you’re not advised to buy vvdi tools for the other functions.)
Part 3: tech support
obd2diy.fr will offer professional tech support for fvdi, fvdi2 and vvdi2 key tools from experienced expert, including software authorization, installation.
Xhorse (VVDI2) will have better experience and tech support than FLY (FVDI2)