Hi amdee,
I suppose keeping your FSW application is better, because it's one of the way to avoid a risk of rejection. Also, it probably has multi chances of getting PR sooner.
And... in the past, some (or many) FSW seniors applied for CEC because they couldn't wait PR under FSW. However, many of them didn't withdraw their FSW applications. I guess there are an important reason...
Hope this help you
Below is super superfluous. I can't be bothered to leave links and evidences. I think that I'm not a drank ;
I think there are some merit and demerit of withdrawing your FSW application.
In my opinion, the (probably my own) best way is :
1. Apply for CEC,
2. Get the medical request for CEC, and then
3. Withdraw your FSW application if you want.
Some of our friends said that they are considering about switching.
If you withdraw your FSW application before your FSW processing start, you will get refund.
It's probably a good way to avoid spending extra cost.
On the other hands, current CEC is more difficult for getting PR than before.
As I heard from some immigration lawyers/consultants, if the application documents had some gaps or unclearly things, or if the officer(s) had some questions about applicants' personal history, CEC experience etc, target CEC application will be refused directly without requesting additional documents.
For example, (maybe you know already or can see details from some threads of the CEC forum / immigration consultant's blog / etc), some CEC seniors were refused because they didn't send the letter from their client (though CEC's document check list doesn't require it).
Some CEC seniors were refused because they didn't send their responsible manager's business card (though CEC's document check list doesn't require it).
Although CIC webpages (CEC application guide, checklist, and any documents) don't mention so, if the wage is lower than the average, the CEC application will be refused directly... In the past, CEC applicants got PR even if their wage are lower than the average, but currently those cases are history. (I guess it's no problem for you... as a skilled worker who has a regular work permit, your salary must be higher than the average.)
Therefore, "withdrawing a FSW application before you got PR under CEC" has a bit of risk.
But please remember, you can get many details, ideas and informations from CEC forums so you can get PR easy.
Another aspect ; If an applicant was refused due to his/her medical result, it means s/he can't get PR under both of CEC/FSW.
Therefore, if s/he got MR, withdrawing another one is not danger.
Because CEC currently takes 10-12 months for MR while many FSW applications wait almost 1.5-2 years for starting their processing, I guess if you apply for CEC now, you might get a medical request before your FSW processing started... but if CPP-O will work more hard hard hard and quick quick quick, your FSW process will be started before you get MR for CEC. I don't have any confidence, I'm afraid.
Anyway, we can choose but I suppose it depends that how important PR is... if PR is absolutely important for one's life, s/he may not want to give priority to the immigration fee.
Thanks for reading this.