Yeah, the RCC showers might have better water pressure, but the ANA experience is much, much better. The showers are totally great there. There's food. There's Japanese customer service, as opposed to more UA attitude.
The only reason I can think of to use the RCC is to make itin adjustments or if it's next to your gate.
Last time I went into the ANA lounge, they just reminded me that I have to watch the clock, as they don't announce UA flights.