Q: Which is the best SD card reader to buy for use with 15" MacBook Pro ?

Read this whilst you are waiting for opinions: http://support.apple.com/kb/HT3553

How old is your MBP?  Isn't there one built in?  All recent MBP's have an SD Card slot on the left hand panel just next to the headphone socket.

There is very little difference between external USB card readers except in their ability to read very high-capacity cards. If you buy one that says it can read SDXC cards, you should have no trouble with any lower-capacity card. Many readers are generic, and are sold under various brand names.

There are SD readers that fit into your computer's Expresscard 34 slot, but they are much more expensive than USB readers.