Regarding the bedding, UA doesn't offer mattress pads on all flights (usually just the longest flights of 12 or 14 hours or more), whereas JL offers the Airweave mattress on all TPAC flights. IMHO this makes JL bedding the clear winner. (I really like the Airweave mattresses.)

As for lounges, doesn't it depend on the airport? If the airport has a Polaris lounge, UA wins. But at HND, UA only offers the T3 ANA lounge which is terrible. At NRT I think the UA lounge beats the NH lounge just because it's less crowded, but JL business pax can use the CX lounge which is also quiet and pleasant.