I won't post negative but would definitely say, Professional level exam requires more than just practice tests from Whizlabs. I used combination of braincerts + whizlabs and other websites as well. Passed it last month.
Exams are out of date (unless they have just updated them). Till then using these sites for practice is fine.
Questions come from all tests (sys ops, dev, saa ) in SA Pro so thinking it is just scenario based is wrong ( I mean those are free marks if you have already passed those exams)