It's been a success for me. I've noticed a big change, since the new year, in regard to approval times. Some of my files have been approved within 24 hours!
I have 786 images that are all cut out PNGs. I had 885 sales in November, and 817 sales in December. 435 sales so far this month, so I'm getting a payout every month.

From Canva on March 27th:

"I recommend you don't hold much expectation for isolated files being cut out by us.  We already have close to 1 million in the queue, and we pay a high per-file price to have them cut out to a high quality standard.  We're looking through the queue for super high quality files on the subjects that are in demand from our customers, and prioritising these.  And it's still going very slow due to the cost. 

It's possible the files you have in the cutout queue will come through shortly, but it's more likely they'll take years, and certainly possible that some will never be done. 

So that's why I encourage you not to have your expectations for isolated images too high."

Anyone had vectors taken yet?

Yes, very recently, but not yet sure if we are a good fit. Too soon to make a conclusion. I do better with evil corporations.