The overall process is a positive experience, because:
1. I did not perform very well in the first screening, but they are willing to give a second chance. I like such flexible and practical style.
2. When I eventually proceeded to the on-site interview, their tech interviewers are very reasonable. They do not require you to write 100% correct code, and they are willing to interact with you during the process. Not every company can get this process right, not even some big name companies.
3. The OfferUp employees are all passionate and believe in the future of OfferUp. This will definitely bring a better working team culture.
4. Although I did not get the offer, but at least they are willing to call you to communicate their decision and even mention the reason. Rare company will be such frank.
I wish OfferUp all the best.