I think for 330 a night you get the lowest level of PH room which is nice but rather small for that hotel, although still large by Tokyo standards. I prefer the next level room (Park Deluxe) which goes for about Y4-5,000/night more. If you are a diamond, you may get upgraded, but it isn't guaranteed at this hotel. You will also get a modest continental breakfast in your room as well if you are a diamond.
Elsewhere in FT, people have commented that not all Club rooms at the CH are remodeled and the older rooms are not so hot, so you need to check on whether you're getting a remodeled room. For 180, probably not guaranteed.
Is the difference worth it? In the end, it will depend on whether staying at a great hotel is worth $150 a night more (plus, in both cases, 10% service and approx 7% tax).