Pros
Flexible working environment and hours (to some degree) depending on your contract you get to work from home and or get flexible working hours (starting a little later and finishing a little later if you need). You'll work with some really cool and intelligent people. Most of whom are actually really nice and friendly on a personal level too. You can get subsidised gym membership and childcare vouchers. You may get to travel (depending on your team). Annual customer conferences and other events happen throughout the year so you may get to go abroad to some pretty cool places! Growth opportunities. While the company is reasonably small in size, if you put the work in you will be offered the opportunity to progress and take on more responsibility (also rewarded in pay rises). Even if there isn't a specific job role open, if they think you deserve more money or a new role entirely they will provide you with the opportunity to take this on.
Cons
The CEO has high expectations (not necessarily a bad thing) but does tend to micro manage a little too much. He tends to get involved in things a CEO typically shouldn't be involved in (needing to be the one that approves everything instead of leaving it up to his senior managers). Leaders should be hired to lead and feel inspired to make decisions but they all have to run everything past him which wastes time and often slows things down. Truth is, you either get along with him or you don't. If you do, for the most part your relationship will be fine, he'll teach you new things and give you opportunities to contribute. If you don't get a long with him, try to. It will only work against you. Company culture does need some improvement. HR need to do more to facilitate employee happiness. No employee surveys are carried out on satisfaction yet the company sells a tool to create surveys even promoting this to HR professionals!