Vantaggi
Friendly atmosphere. Fairly "flat" structure (not many levels of hierarchy but it's steadily getting worse). Adequate compensation. No issue taking days off for personal reasons, flexible working hours. Used to have a real "small/challenger company that can do it" spirit, you can still find it occasionally but it's getting less and less common.
Svantaggi
No pay increase (unless you're top management). Top management is also out of touch with reality (let's implement "lean" in three months, yeah sure...). Human resources are basically non existent, you'll only meet them when you're hired and when you're fired, no career planning, formation plan... Company has outsourced lots of core activities (network, IT), making everything more complicated (and costlier in the end).