$149 is the discounted price - and at that price, must be purchased 3 or more days before you want to start taking/printing photos - so buy it at least 3 days before you start your vacation. Full price is $169. I doubt you'll find it for less, but if anyone else has an in on a better price, I'm sure they'll share.
I don't have pics anywhere online that I can share from. But I can say that the photos definitely range from fairly mediocre to quite good. They're taken with decent dSLR cameras. Some photographers are better than others. I've blown up one of the photos from our 2014 trip to an 18x24 canvas that's hanging on my living room wall. My favorite photo of the vacation, and I bring my own dSLR to the parks as well. We've had some really great experiences with some of the Photopass CMs - we've had several go far above and beyond. But of course, most simply do what they must. Many photographers (though not all) are trained to take Magic Shots - those are fun, and totally worth asking for when you don't have a line of a dozen people behind you. If you haven't seen them, basically, the photographer will pose your group, and a bit of Disney "magic" (in the form of a character or digital "prop") will be added to your photo when it's processed. Very cute. My son loves them. We stop at most Photopass photographers we see (though not all) - it's usually just a few minutes to wait until another group or two have their photos taken. If it's not ridiculously busy and there isn't a long line of others waiting, we ask for specific photos when we want them - like one of just my husband and me together, a silly pose, etc. And we almost always ask for Magic Shots. We let the photographer suggest other poses. Again, if there isn't a long line of others waiting. When it's busy, we take a shot or two and move on. We easily end up with 300+ photos over a week's vacation. And then you can add details (like character signatures, borders, etc) to the photos on your computer, if that's your thing. Again, it's cute stuff.
For me, the best thing is that we're all in the picture. I'm always the one behind the camera. With the Memory Maker/Photopass option, I can prove that I went on vacation with my family.
As for whether it's worth it, we don't do a Disney vacation without it. To us, it's totally worth it. Whether it's worth the cost to you and your family is something only you can judge for yourself.