At first, Google Glass was a rarity. Explorers were members of an exclusive club. Nowadays, the club is still invitation only, and you can still turn heads wearing one on the street, but for anyone who wants to put Glass on their face, it's just a matter of a little time and a lot of money.The i ncreasing number of Google Glass invitations being sent to beta testers means that tech-savvy early adopters are struggling with an expensive question right now: is Google Glass worth it?To answer that question, I turned a critical eye to Google's sci-fi-looking wearable computer and tested its latest Explorer Edition of Google Glass. With the sound of my voice, I took hands-free photos by saying Okay Glass, take a picture. I instructed it to upload the resulting point-of-view image to Twitter and Facebook and attached a caption, all with voice commands. I saw flight information automatically beam to my eye with a gentle Google Now reminder the day before traveling.