Let's start by saying each is entitle to his/her own opinion....

The JW CL is enormous. There is a main seating area, with very comfortable chairs and a long bench with huge pillows. There is another seating area in the hallway just outside this room and outdoor seating on a deck. There is an island with chefs working in the middle preparing fresh entrees. There are more attendants. Just outside the front door, there are a couple desks with actual Concierges making whatever arrangements you need. The other hotels are much smaller CLs, although both are large by US standards. Both have many food options, but not quite as much as the JW. At the other two, the servers double as the people helping you at the desk.

BTW, I like the rooms at the Ren and FS better, and have been upgraded consistently at both. I have not been upgraded at the JW, beyond having a CL level room. (I got a corner room at the Ren this time, not a suite, but I made my reservation at six in the evening, after rooms had likely been assigned for the night.)

With that said, it's a little harder to get to the BTS from the JW. The shortest walk is under a pretty messy highway underpass. It's not on the SkyWalk. It's one stop over on the BTS, and you cannot access the BTS without walking outside the entire way. It is, though, relatively easy access.

The JW lobby is a little larger and a little grander. It is next to a small complex, connected by a covered bridge, that has a few inexpensive, good restaurants and a supermarket, which is nice.

The FS is beautiful. The service is impeccable. I'm not sold on the location, but I like the bustling, touristy area. Not everyone does. If you are looking for a more laid back area that is more Thai than touristy, the FS is a winner for you. It is close to a BTS station, but you do have to cross one wicked busy intersection by walking into the middle, standing on an island while cars and scooters whiz by within inches until you can navigate the other half of the crosswalk. At no point do cars stop in both directions allowing you to cross the entire street at once. There is no pedestrian walk signal.

Putting the construction at the Ren to the side, I'd choose whichever of the three properties is cheapest. Each has plusses and minuses. I'm on points this week. The FS was 80k, while the other two were 120k, so I'm at the FS. If I were paying out of pocket, I'd likely be at the Ren. It's got the lowest rate this week. All three are excellent hotels. If any were in Pittsburgh, Dallas, Chicago or LA it would be, hands down, my favorite hotel in that city.