Having had a good look on the map now, the BW Premier Arpoador seems to be brand new and is indeed in a good location, albeit not a typical "aspirational" location (i.e. spectacular sea & mountains view). If you don't necessarily want to use points at the BW, I ran some options on Kayak for a 3-night stay in Aug starting on a Monday:

Arena Ipanema: $100/night
Hotel Arpoador: $110/night
Sol Ipanema: $144/night
Sheraton: $151/night on Amoma (meaning you could BRG it against SPG for a rate of $112)
Sofitel: $187/night (also arguably BRG'able on Accor, which is a farce)

Needless to say, it's only worth considering these if you get a sea view room (all rooms at Sol Ipanema, Sheraton, and Sofitel should feature sea view). The Sheraton is not a consensus here, and it's arguably better if you have status, but a it should be quiet midweek, so a better chance of scoring an upgrade).