I'd agree - plus the LCY service is really only beneficial (in my view) on the Westbound flight - as it's a day flight you can enjoy the novelty of the "private jet" feel, and you get the benefit of short check-in and pre-clearance into US immigration.
On the way back, unless you actually need to be in City/Canary Wharf, I'd vote a decent Club World sleeper seat on a mainline service to LHR as being the better option every time.