Thanks for all the comments. I just came back from a 2N stay there, so thought I'd just add my experience for other FTers.
As I mentioned, I was discouraged from the Marriot, but decided to go ahead anyway for some logistical reasons that I won't go into here.
The hotel was very full, lots of meetings going on. Couple of things that I found a little lacking for the place.
1/ There were no Do not disturb/Pls make up room signs. I have no idea why, I should have asked, but I couldn't quite be bothered.
2/ No armchairs or coffee table in the room. Quite annoying because I had a visitor and there wasn't anywhere to sit other than the bed and the one swivel chair at the desk.
3/ One miserable bruised apple. Talk about wimpy. My previous experience at the JW Marriot HK was at least a small fruit basket and welcome hot chinese tea. Rennaisance Saigon too delivers a fresh fruit basket. Malaysia has plenty of local fruit available, there's no reason for this half-hearted effort.
Even at the Hilton Hanoi where they don't do fruit baskets, I get a plate of chocolates and the common floor lobby is well supplied with fruits for the taking.
4/ Minor quibble, but what crappy TV station offerings. 4 local channels, CNN, ESPN, Star Movies, Discovery, NHK, and 2 new channels called Vision 4. Not up to par for a JW Marriot in my opinion.
5/ NO CLOCK. Drove me nuts as each time I wanted to see what time it was, I had to look for my watch. There was no time on the TV, no alarm clock panel, not even those screwed to the bedside table clocks. Sad.
I haven't much to say about the service. It was there. Not poor, but certainly not on par to many places I've stayed at. For friendliness, nothing beats the Renn Saigon for me. Cheery, accomodating staff and always a smile and going the extra mile.
I'm not planning to return to JW Marriot KL any time soon. The Sheraton Imperial KL comes highly recommended and for the same rate too. I plan to book in there next time.