gpapadop - there are many threads on this which you can find with search. The biggest difference is that Gold gives you 3 points per dollar, while CP gives you 2 points per dollar. But CP will give you 2000 point on the calendar year 5th and 10th stay. So depending on your number of stays, and also on your average hotel bill, Gold may be better than CP or CP may be better than Gold for earning points.

Another difference is the 1500 min. point transfer for airlines for Gold. I believe (but not absolutely sure) that it is 2500 pts for CP.

Comments in FT suggest that upgrades are same with either.