More than 2/3 of the economy cabin is regular economy seats so using the "there's more legroom in E+" line isn't applicable for most travelers.
Even if you consider the extra legroom in E+, the seat width is less than on VA, DL and QF, so it won't necessarily be more comfortable in E+.
UA is far inferior when it comes to IFE.
All-in-all, UA offers the worst economy experience for LAX/SFO-SYD, IMO.