The starting pay in the Silicon Valley office is not as competitive as other companies in the area. If you're all about the money, there are plenty of soul-crushing jobs available elsewhere. To me, the small sacrifice in pay is worth it for the environment I get to work in and coworkers I work with. There are no bonuses, but I do a pretty good job, so my raises are pretty nice (10-15k/year).
Some engineering teams are working on/with technology that is brand new, proprietary, and/or very low-level. This can make it a challenge for both new and experiences employees to feel like they are succeeding or performing optimally. As a very documentation-oriented worker, it has been frustrating at times. Most of the time, others are receptive to requests for help, though.
The benefits are probably mediocre. Definitely better than nothing, but I am actually signed onto my wife's benefits because it worked out slightly better financially (stipend from SoundHound for waiving benefits > cost of adding me to my wife's plan). Medical plans include high-deductible HSA (free), PPO, and HMO (Kaiser). There is a 401k program, but no 401k matching.