On August 12th, I migrated this site, which is not a small site, from HTTP to HTTPS and honestly, the migration has not been bad at all. Technically, it only took maybe a couple of hours, including spotting and fixing 99% of the miscontent match errors and rewriting URLs, 301ing, fixing images to make sure they are over HTTPS and more. But on the traffic side, I have not seen much of a change.
And according to a Google News Help thread, it seems many are in the same boat.
I personally did this, so I could jump in first, and report back to you if it is safe. It seems safe, but let me share my results. First Webmaster Tools search queries report:
HTTP version drops around the 12th but note, the top line is 1 million impressions:
HTTPS version climbs up, but the top line is only 800,000 impressions:
When looking at organic Google traffic, comparing August 13 through September 17th to the previous time period, I see a -2.54% drop in traffic, which is not significant based on how much traffic the site gets.
The more worrisome is how Bing and Yahoo handled it. Bing shows a -7.87% drop and Yahoo shows a -9.20% drop. So keep that in mind!
I do hope this helps others. I'll report my RustyBrick site migration later on, probably at SMX East.
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