I did say the location was better w/ Marriott. But it's not like the IRS is in bad location. If upgrade and lounge are important, OP has better chance with IRS. For 2 day stay, both are good with nod to Marriott on location. However, the walk to corner for IRS is a 60-second walk and then few minutes to main area on tram. OP has to decide what is most important to him. Quite frankly both hotels are good choices, which a nice choice to have

Cheers.