It gets a lot of flak because it shows a Vantage score instead of a FICO. That being said, if all you’re trying to do is build and maintain healthy credit, CK will show you all your accounts, balances, pay history, average age, and mix, and its FREE. All those components make up any credit scoring model, so the better they look, the better your credit looks. Just understand that most lending inquiries will use a FICO score, so the score CK has will not likely be the same as your FICO. If youre going to add a bigger line of credit, I’d say to get a free FICO from experian, or pay for a full report to know exactly what you have.
Also one note, there are several FICO scoring models, as well. Some geared for cars, others for mortgages, and so on. You will never have just one blanket credit score, so focus less on the score and more on the factors behind the score. Pay your bills on time, keep your balances low, limit your inquiries, keep your oldest accounts active, and try to keep a mix of revolving and installment accounts if possible.