While I have not tried any other brand, the DigiGear adapter card (blue one) I bought through ShopDigi works flawlessly (http://www.shopdigi.com/product.aspx?pf_id=CIDA2
I had first tried their high speed version (green card), but it was not compatible with my D200 (think because of the high speed aspect).
At the time of this posting, the cost on this card is $14.98, and the shipping is free. If all you're planning to use it for is as an adapter for regular SD cards, it should be fine. As far as using it with an Eye-Fi Connect X2 SD card, it won't work for that.
Should add that their customer service is very good. You can actually talk to someone and they'll help troubleshoot if you need it.