The Le Meridien you mentioned is leaving Starwood at the end of May this year.

I, personally, see little difference between the location of the Westin and the Sheraton Miyako in Tokyo for convenience.

Whilst I won't argue that the Westin is better, there's a law of diminishing returns at work here. IMO, the Sheraton Miyako offers excellent value with points (especially with cash & points).

Sheraton Miyako has the same Sweet Sleeper beds you'd find elsewhere - but it's likely you'd get twins with an award.