A paper titled "Squaring Venture Capital Valuations with Reality" [1] was recently published by students at Stanford GSB that put forth a new model for valuing privately held companies [2]. If you consider "Table 8: Detailed Unicorns Fair Values and Post-money Valuations", Uber objectively has one of the smallest deltas of all valuations listed at 12% (bested only by Snapchat and Lyft out of ~100 companies).

[1] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2955455

[2] https://www.gsb.stanford.edu/insights/silicon-valleys-unicor...