I've stayed there too. I was quite pleased. I think it used to be a Sofitel, but now it's pure Marriott.
As noted, it is quite near the Metro so it is very easy and quick to get to the main tourist areas. Depending on how long you'll be there, you could buy a 'carnet' of 10 metro tickets or look into some of the other options for longer stays (A weekly pass--Ticket hebdomadaire-requires a small photo. There is also the more pricey but flexible Paris Visite pass. Both of these give unlimited trips in a certain time period). For more info:
http://www.ratp.info/touristes/index.php?langue=en