I was just 2 weeks ago in both of them and frankly both of the properties are having serious issues.

Firstly Ritz - the renovation is still ongoing, there is awful cleaning smell in the main lobby in the mornings and the corridors stink of paint. I was allocated executive room on 20th floor and the whole floor had very strong fresh painting smell, which later caused allergic red eyes. To get to the rooms you have to pass the conference section and in my case I had to push through some coffee breaks of the events to get to the other side. Main gym is closed and they have set up a temporary one with half-broken equipment in one of the conference rooms. I do not know how slow is their complimentary internet, but the super-premium one they are selling at 100MYR per day extra (at theoretical speed of 2Mbps) was too slow for making VOIP calls...
What was nice was the breakfast in Cobalt room, one of the nicest I have see in Malaysia.

Secondly, JW - they have renovated the lounge to non-window room on 3rd floor. Quite clueless staff, but offerings OK. Rooms are waiting to be renovated in very coming future. As Gold was upgraded to executive room (compared to standard one it just has high ceilings). As it is old, then during the shower the water temperature was changing from ice-cold to burning hot, at least in Ritz that was stable. Internet was equally bad as in Ritz. Breakfast in the main restaurant was weaker compared to Ritz. Points for the stay never posted... even after contacting the hotel again on the matter.

Both properties had some more issues and frankly I was happy to leave. Perhaps they could be worth of return after some years once they have managed to complete the renovations and train the staff a bit more as well, otherwise choose a different place, there are plenty to choose from in KL.