Pros
I found Celfinet's project(s) to be a great technical challenge, in terms of software development. Telecom is a tough domain requiring interesting skills and study to fully grasp. While I participated in the project there was openness to introduce some good technical practices and start-of-the-art development techniques, though not always fully accepted or adopted (such as TDD, CD, CI, Agile techniques, etc) In general, most of the people that where in the company where great to work with and friendly / respectful. There were great devs on the team, but unfortunately most of those have already left, or are on the move. I was fortunate to have been able to interact and work with many these people, and have grown with it.
Cons
When reading the following, please consider that I no longer am a part of this organization, which I left as a contractor due to delayed payments, and am still lacking in (2 months of) payments. My review is as impartial as I can make it. I find company culture and organization was it's largest problem. They sell them selves as an Agile and learning organization, but in many ways, it currently is all but that. When the group was smaller, there may have been less need for supporting roles, but rapid growth without the necessary foundations (training organization, HR resources, decent equipment) made work stressful and disappointing. Too much was requested from a team in many ways without the necessary knowledge or resources to perform efficiently. Tooling was in most cases deficient as the company is generally unwilling to spend money on software and tools (you would expect everyone in a MS shop have a R# license, right?). The tech center in Porto, where the "R"&D department is situated ("R" is because no research is truly done there, only development), is lacking in meeting rooms and decent whiteboards, and reviews are done in the open work space, but with all the noise associated to it. Devs will work with sub-par laptops - i5s with no SSD, and a 2nd monitor can be hard to get. Open-space noise is typical and noise-canceling headsets are required for focusing. "Scrum-but" is practiced - most of the ceremonies are in place, but only to serve as an Agile flag. Micromanagement efforts are growing, and suggestions for changes by team members are squatted or ignored. They know the words on the manifest but not the meaning. Meaningless estimates are requested, but for an incomplete and requirements-missing backlog. Most of the product owners are overbooked and unable to present useful requirements (though this has improved compared to the past). The scrum-master is anything but. Training is deficient, also. There is no true training initiative. Most devs are sent to the Agile Portugal conference event (in Porto) and some are offered a workshop. New devs are many times contracted based on availability and not on skill level. As of late, pretty much every senior dev has left, and pretty much every dev / op / qa has in one way or another been looking to move on from the company. Most consultants who had been working long term were sent off. The company is currently in "the dip" in it's project. There is a heavy lack of motivation throughout the team, which has motivated many exits, and there is no evident strategy to avoid the short turnaround. Finally, the lack of transparency may be one of the companies worst enemies. It's thought by many that the company is going through some financial troubles. There has been a clear lack of respect for consultants in terms of pay - as of 2016, payments have been constantly delayed and payment in many cases as my own has fallen to 90 days (on a 30 day invoice). During 2016 there was a clear cancellation of contractor work (though with no less volume of work needing to be completed). There have been movements in upper layers of management and re-orgs, supposedly in order to enable the company to grow more and improve, but most are based on what i'd call "buddy choices"; Politics over merit.