Pros
Fantastic perks. Brilliant coworkers, smartest group of people I've ever been around. Bonuses have been great in recent years. Work can be quite interesting and there is no red tape in between you and getting your ideas out there and implemented if they show promise. I've seen new employees hit the ground running and make significant contributions quickly. Great trader training program. If you are very motivated (or a genius, although I've seen some really smart people get cut) you can do really well for yourself here. Decent hours relative to some firms in the industry, although you can get better hours elsewhere.
Cons
Lots of pressure to always be on top of your game. They will not hesitate to cut you if you can't keep up with management's standards. A sizable portion of your compensation is determined by your individual performance, where the standards of judgement can be unclear. Management, who is responsible for this, clearly plays favorites (usually the top performers, but not necessarily). They are also very unforgiving when you make mistakes or need help to get something done. The management claims there is no stack ranking, but you're performance will be measured up against your peers come review time. Not much meaning behind your hard work other than making more $$$ if you care about that sort of thing, so you will need to find motivation elsewhere. Guess it comes with the territory. I've seen certain members of management lash out and/or demean certain employees. Abysmal profit sharing/bonus scheme relative to other firms in the industry, especially for dev roles. Skews very heavily towards the top who's contributions are not clear. That being said, pay is still great for junior and senior employees alike. Usually not something thats brought up, but a large group of the particular type of brilliant person that Optiver attracts can get annoying or frustrating sometimes if you don't fit in well. Big egos, pretentious personalities.