My 2 cents
The ordinary HI's that I've stayed would yeild at most 2,3-star ranking. Since it's a classic brand, most of the properties are old and room have a very rough feel with the outside style of room entrance. HI-express HI-select and the spin off brands are very much more new and modern at very similar prices.
My opinion of CP's on the other hand is just the same as everyone else, 4 and even 5-star quality. Very high end, actually, it could be considered the highest level brand in the intercontinental hotel group other than the intercontinental hotels themselves but avaliable in many more locations than those hotels.