I'm still in the latter camp because I'm not yet convinced that an NS5A and/or nuke will be enough to remove interferon and possibly ribavirin from the equation. (It may still take a third class, such as a PI.)
Data from the dual nuke combo suggests to me that interferon's days are numbered. When you get such speed and efficacy in a dual nuke combo why experiment with other classes which will only reduce the resistance profile of a two drug combination. What VRUS has developed is the new SOC in HCV treatment and in the future three drug combos will be used for nulls in the second line setting IMO.
One more point which pertains to the valuation of the company. There are other developers of nucleotide analogs out there but no other company had the insight of combining a purine and pyrimidine nuke thereby giving VRUS tremendous leverage going forward. IMO all the other developers in this class have half a backbone.