I have used Picaboo for several years to produce calendars for my parents and my in-laws for Christmas. Additionally, I had produced a photobook of our wedding. I have been happy with all these purchases.
I was worried this Christmas (2014), as I saw many negative reviews about the quality decreasing over past years. The calendars that arrived were wonderful, as always. Very happy with the continued quality. In fact, my mother commented on a couple of the images that were old slides we've had converted... that they looked better and brighter than they ever have printed anywhere else. As well, I ordered the calendars on the last day that they guaranteed Christmas delivery and was pleasantly surprised that they arrived with at least a week to spare.
I can't really comment on customer service as I haven't had to deal with any unfortunate issues.
Something new I did learn this year. Though... if you have a Groupon/deal/etc and the expiry date passes, you do still have the purchase amount as credit, but you can't combine it with any other discount offers that might be happening. It seems you must use it for regular priced product. I'm not necessarily thrilled with that, but a)it's my own fault that I couldn't finish a project in the 6 months before expiry and b) there's enough special offers and sales out there that next time, I'll finish a project first and then wait for the deal to print it with. It seems to be an issue with the fact that that you can only use 1 code per order, so after you use your gift certificate code, you can't put in the code for the deal/sale pricing