Pros
Radar fosters some of the hardest-working and brightest individuals I have ever been around. That said, there is no pressure from upper management to work extra hours or run yourself into the ground. It's a company that will challenge you to work your smartest, not hardest. Perks and benefits are great and consistently getting better. Upper-level management is really focused on employee well being. SDR's - all I can say is this position is different from others. If you want to kickstart a career in SaaS and not hate your first year, check out Radar.
Cons
As a young company, things are consistently changing, so if you don't like the idea of not knowing what to expect next, this probably isn't for you. Promotion path could be clearer but they're working on that and it's really up to you to push for something you want. That said, a smaller company means your input is more valuable, so there's an opportunity here to shape the direction of change.