We've been using Signup and OffTheGlass for a number of years now (implemented prior to my joining the support team, so can't comment on implementation issues), and have had no real poblems with it - once it's in, it just chugs along and works. Having said that, until recently, we've also had a fairly simple environment with regard to OTG - monochrome, A4 and simplex printing only. We're currently in the process of having our MFD fleet replaced, which include A3/A4 options, as well as colour. We've also just had our first "embedded" release solution implemented - up until now they've all been of the PS200 variety - haven't had a great deal of experience with this as yet, as the library which has had this done was only opened a month ago. The main comment I can give on that one, is that it's a bit of a learning curve with regard to configuring the printer and Pharos to provide you with the functionality you want (and DON'T want).
Configuring Pharos to handle the new printing functions, however, has been quite simple. Being able to configure the features, and the costs for them etc. is done by way of a nice simple chart-type interface, which is easy to read and simple to understand.