I recently assembled a few systems that required SD storage, so I got some Adafruit micro-SD breakout boards. This week I needed to make some more, and Adafruit is out of stock just now, so I got some from Gravitech. For anyone interested, you can see them side-by-side in the photo below (both are connected to an Arduino Pro Mini 5V, so I made use of the 5V<->3V level converter both boards include). https://www.adafruit.com/products/254http://www.gravitech.us/micaad.html
The shape is a bit different, but both boards work as intended. Both have LEDs, but the Gravitech LED is on whenever a card is inserted (I think using the socket's mechanical card detect switch) and the Adafruit LED blinks while data is transferred to/from the card, which I think is the more useful function. Both have "push/push" type sockets (to release card, push in, it clicks and springs back out). They are from different vendors; the Gravitech sockets seemed to have a bit more friction and were more sticky overall, and tend to grab on to the cards rather than release them cleanly, but they seem to improve a bit after a few cycles.
(I also got one Gravitech full-sized SD card adaptor board, which is bigger but otherwise similar.)