Avantages
Interesting projects, especially for banks and government. If you're good, you will quickly be put on a lead position, and will switch projects before they reach maintenance phase. As a developer / architect you have almost absolute freedom in choosing technologies, frameworks and other toys as long as they fit in the budget. The atmosphere is great even though all the cons, and the people tend to stick together. People are sent to (usually) external trainings, organized by Oracle or (more often) Altkom Academy. The company offers private health-care programmes, Multi-Sport card, social funds, business phones and internet which you could (to some extent) use privately. Also, if you travel a lot, you could get a company car (although this changed in 2012)
Inconvénients
Usually, the freedom of choice is just between open source software. The company will not pay for good developer tools, and getting a single monitor was only for the meritorious in 2013 (yes, devs worked on 15" laptops only), although I heard this changed. Second monitor however is still a luxury. The company develops, and sells mainly in Poland, which - together with lousy management - is the cause of money shortages. Whatever you do, do not show the management how good you truly are, or that you're willing to work extra hours to achieve goals. If you do, they will not pay for extra hours (although I've heard of projects in Sygnity that did, it's not a rule) and they will use you until you die or quit of exhaustion. If you don't, you'll most likely be skipped on nearest salary rise or promotion. The lose-lose situation. The trainings are constrained with a loyalty agreement, forcing you to work for the company for a year or two, for course costs as low as 400 EUR. Those trainings are usually the only way of personal growth, as there's no such thing as a defined "career path" in Sygnity.