I purchased a Replicator 5th Gen a little over 2 years ago. The smart extruder was clearly not ready for prime time. Random problems with it, constant clogging, etc. I had to replace it 6 times until one worked longer than a few prints, only to fail again. I think they have somehow fixed that problem now. The latest extruder has worked find for more than 6 months now.
The quality of the prints varies, depending on the object. Medium to large size generally print better than smaller objects, even at the highest resolution. Extreme detail in smaller objects is difficult to obtain, but I'm satisfied with the quality of larger objects. Definitely not for prototyping small pieces, for example, small jewelry.
The printer is easy to use for beginners and is probably not what you want if you are a true tinkerer; there are other printers out there that lend themselves to all sorts of experimentation.
Mine is out of warranty now so I don't care about their policy of voiding warranty by using third party filament. That is among the worst that I can mention. Makerbot doesn't have a large variety of colors or PLA filament to begin with, and they should be opened to people using other filament vendors. I have found that Faberdashery filament is one of the best, but every time I use it, I wonder if there is something intrinsic to the extruder that won't allow me to make a successful print. For the most part it has worked.
Makerbot announced new types of composite filament about a year ago and I guess that is no longer the case. I was looking forward to try the limestone, and iron composites but it never happened.
Their customer service is severely lacking. The fact that I had to pay $100 to open a support case was the last straw. With such bad customer support, maybe they should focus on having a database of printing errors that one can search and maybe try to find answers.
Maybe the latest Makerbot 5th Gen has been greatly improved... I admit that I am tempted, but I have now began to search other technologies for my particular prototyping needs (jewelry), and already acquired an SLA printer to learn and explore that technology.
Finally, my school has 3 5th Gens, and a Z-18. I have used what I've learned from my own printer to be able to troubleshoot the problems of the Makerbots in my school, and they all keep running successfully now. I guess, that would be the silver lining.
I would recommend its purchase because it is really easy to use, with nothing to assemble after unpacking, but I would also recommend caution. If purchased for a school, I would also recommend to invest in the training program to really learn how to troubleshoot it, since customer support won't be likely to be satisfactory.