I have had a complete nightmare with the eRX groupset. Managed to get the grand total of 1 mile on it before the rear derailleur stopped working, not a problem as these things happen. Dealing with L-TWOO support is another matter... You basically get a small window of around 5 to 10 mins at around 8AM UK time where they read and may reply to your message and then that's it, they are gone for another 24h. It's taken 6 weeks to get them to agree to send me a replacement rear derailleur. In that time I have ordered a 105 Di2 groupset from China, waited for delivery, uninstalled the eRX and installed the Di2 and ridden 120km.
Cannot recommend, the replacement still isn't here