If I'm thinking of the same hotel, I stayed at the Landmark about 5-6 years ago when it was a Regent and though not the most centrally located, I though the location was fine. I liked the property then, I seem to remember the guestrooms were somewhat larger than the London average. But, I have no idea how it rates under the present management.

I also Loved the Lanesborough, but am a little aprehensive about it now that it is now as a St. Regis property.