The price is cheaper than other online printers in general. They have updated their website user interface couple years ago, so that it was better but still behind other big online printers. (For example, web interface of GotPrint current site is like the older version of Vista Print website.)
I'm a designer who has been using GotPrint for over 5 years, so I have experienced their ups and downs. Since I'm in-charge multiple of my clients' accounts, I felt consistent customer services and printing quality disregard a small or big account couple years ago. The quality was decent for their price, and occasionally they were able to produce the print order faster than their standard turnaround time (4 days) back then.
Two of the major drawbacks are the customer services and turnaround time now. I have interacted with a few different representatives and a couple of them were not professional, rude and unhelpful. They didn't really offer any solution and escalated my frustration instantly, not until I talked with the right person who tried to help. It happened that my 2-days rush printing took over 4 business days and they gave me attitude. In the end, my 2 days rush shipping and one day shipping order took over a week. It was quite a disappointed and frustration process, and they were not reliable.
Overnights Print as all-in-one-printer with fast turnaround
Moo for high quality printer
Primo Print for fast and decent quality printer
You get what you pay. Because it has happened a few times with their long/inconsistent turnaround time, I would only use GotPrint when you want something cheap, and you don't expect to receive anything for 2 weeks. I found myself surprised a couple times that I received the products on-time.
If you have a time sensitive project and expect something within 5 business days with rush shipping and printing, please use other printers.