I keep a spreadsheet of hotel prices for various dates that I target... looking at the last few months, for a sample of 10 different date ranges I end up with the following averages:
Aloft 2500 THB
4P 2900 THB
CY 3100 THB
ROS 3200 THB
In a city like Bangkok I just don't think it's worth saving a few dollars and pick Aloft and 4P. As much as I like to mix things up and try different hotels, I cannot get myself to book at those two hotels because at these prices it simply does not seem like a good deal to me. As @
CJKatl mentioned, if you are Platinum you just pay $20 more and you get access to a lounge, better breakfast, and ROS even has good odds of suite upgrades. I have booked at Double Tree and Hyatt Place before, which could be compared to Aloft and 4P, but always on short stays when Hilton and Hyatt had good promos going on which made the net cost of my stays quite cheap. Given that Marriott does not have promos worth talking about these days, saving money to stay at Aloft does not sound like a good idea to me except if you absolutely need to stay in this exact specific location.
And speaking of Marriott Marquis, while the average is 3900 THB, I have seen it below 3000 THB on occasion depending on dates; at this price in my humble opinion it would be nuts to stay at Aloft for 2500 THB. If one does not have status at any hotel chain I can see if, but if Plat, then no way.
That said I have never stayed at Aloft so feel free to take my opinion with a grain of salt...