What's the advantages of say Wheeltop/ Shimano vs purely Shimano Di2 or SRAM electronic??
Chinese electronic groupsets have a few advantages over the established players, but they only apply in special cases:
1. Wheeltop/Ltwoo are compatible with 12/11/10/...-speed cassettes/wheels while with Shimano/SRAM you are locked into a given speed; this is relevant only if you have older wheels you want to keep using
2. Wheeltop/Ltwoo allow you to tune the position of your rear derailleur for each individual cog of your cassette; this is nice if you have an ornery cog where despite your best efforts the chain acts up
3. Price - depends on your region
4. Weight - Wheeltop/Ltwoo are marginally lighter compared to the equivalent components from Shimano/SRAM