I was referring to how many more Volkswagen cars are able to see Xtool X100 Pad 2? Unlike the EZ500
Answer to their difference:
1.    VAG VW 4th 5th IMMO key programming (+& -)
XTOOL X100 PAD2 FULL Set can program VAG VW 4th 5th IMMO key, here a post on how to do:  http://blog.xtooleshop.com/xtool-x100-pad-2-full-set-program-vag-vw-4th-5th-immo-key/
If your XTOOL X100 PAD2 without VAG 4th 5th IMMO key programming function, order a KC100 adapter, this is a little bit expensive, maybe you contact the seller they would give you discount especially when they promote.
2.    4 system diagnosis VS full system diagnosis
You can see XTOOL X100 PAD2 have four systems diagnosis (Engine, Brakes, Central Electrics, Airbag), no full-system diagnosis. And XTOOL EZ500 have full-system diagnosis option. EZ500 is powerful with many functions and vehicle coverage, I already prepare a post on all EZ500 functions and testable car models & year:
3.    Price is difference
Xtool x100 Pad2 plus VAG 4th 5th immo key: $879 incl. shipping cost + one year free update online (One key update) + after-sale support
Xtool x100 Pad2 with no VAG 4th 5th immo key: $689 incl. shipping cost + one year free update online (One key update) + after-sale support
EZ500 (same as ps80): $769 ncl. shipping cost + one year free update online (One key update) + after-sale support
View more XTOOL Brand products: http://www.xtooleshop.com/