According to BCN Japan, half of the top 12 lenses sold in Japan for Alpha mount cameras are 3rd party lenses. What I can make out of it is that all top 12 lenses do not have in-lens image stabilizer and if you compare this with the top 10 lenses sold for Nikon and Canon, it shows that 3rd party lenses fair quite well. Click on the BCN logo below to go to the rankings, it’s on page 2 of the listing.
On another observation, none of the top 12 lenses sold for the Alpha mount cameras are high-quality professional lenses. As someone mentioned before, Sony are for newbies!
The surprising thing for me is that the top selling lens is the one that I had and found it horrible. I exchanged it for the 3rd best selling lens instead and got myself the 9th best selling lens to cover the range. In simpler terms, I got rid of the SAL75300 for the SAL50F18 and separately bought the SAL18250. These are the 2 main lenses that I use these days (in addition to the occasional use of the Minolta 70-210).