Pros
SoundHound is definitely one of the best places I have worked at (having been at FAANG companies before). I am particularly enthralled by the types of research problems we get to work on. It ranges from core-NLP to some intricate engineering problems. Since it's a mid-aged startup, you get to also interact with a lot of cool people on a daily basis, which is definitely a plus. Other than that, you also get a lot of perks/benefits which you expect from any IT-based company these days.
Cons
Sometimes, you may be facing strict deadlines but it also largely depends on which team you are in. Communication is very important since the codebase will be fast-changing and often you may encounter problems related to code versions (even if you are using things like version control!)