Wherefore art thou, Hilton Kuala Lumpur?

The hotels are both in the same building and share facilities but the Hilton has many reasons to be better: Hilton is Hilton's flagship brand, Le Meridien is not Marriott's. The Hilton has 50% more rooms. The Hilton was more recently renovated. The gym and pool facilities are shared, but operated by Hilton.

If the price is equivalent, and you're unaffiliated, take the Hilton.