In a word? "NO". CK has it's use, it's good for monitoring accounts, but the score is useless. Why do I say that? Because you will not see a creditor approve nor deny you credit based on their score. I've seen my CK score over 100 points off of my FICO score. They use different criteria and methods of formulating scores.
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
Take the myFICO Fitness Challenge
Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.
Took me not quite 2 years. How'd I do it? This forum, working lots of overtime and a small case of OCD!
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
Take the myFICO Fitness Challenge
Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.
More than willing to give you my journey. It'll take me just a minute to type it, so hang on. 
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
Take the myFICO Fitness Challenge
Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.
We decided to buy a house, but my credit was horrible. Wife took care of the bills and wasn't quite so dilligent at times. Plus, we had some rough spots that limited our resources. I took over the finances and made it my primary concern. So I came to this site, started lurking, then asking questions. Number one rule was that their would be no more baddies. I had to stop the bleeding before I could fix the problem. Below is my suggestion to you.
1. Pull your CRs from www.annualcreditreport.com. It's free, "federally mandated", don't buy the scores they're worthless. Now you want to go through each tradeline and mark what's good and what's bad.
2. What's good.... Keep it good!!! No missed payments!
3. What's bad.... Break this down to 2 different categories. Paid and unpaid.
Paid... This is where you start the GW process. I would send mine out about every 3 weeks. Looking for any names, address.. etc. that I could find. I had been told no several times, but eventually, I'd get someone to either give me a break, or just get rid of me and delete.
Unpaid... Here I started with PFDs, again, looking for names and addresses of anyone I thought could help. Usually a VP or Finance Officer. I would try a few times with this, then, if nothing was going anywhere, I'd pay/settle, then throw it in the paid category and start the GW process.
Now, there were a few that had improper listings that I had to go deeper into to get to delete, but this is the general idea.
I then got a small CC, started with GE Walmart and it snowballed from there.
Now I just garden and try to help those I can here. I have my new house, living within my means, "which is so much easier now".
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
Take the myFICO Fitness Challenge
Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.
