I got my copies of S1 and S2 through the DD sale. I'm almost through S1 disk 4 with no issues on my Oppo player that hasn't had a firmware upgrad since I bought it about 14 months ago.
While my Costco has copies of S1 and S2 i found no S3 available. Hopefully they aren't all out yet and...
DeepDiscount. http://www.deepdiscount.com/
Part of their Presidents day sale.
Code: PRESBLR
The website is a bit flacky at times clearing out the cart.
While it may be a bit risky since DD has not had the best reputation of late, TZ S1 and S2 BR's are on sale as a B1G1 Free deal that comes out to just under $40 a season shiipped.