Astralis are very good value for this event, I also feel there is enough value there in hoping for a straight run from both Astralis and VP.
It is often the case in these type of events that the teams playing in the earlier rounds come in well warmed up for the bigger games later on and cause upsets. In this case, I can easily see Astralis beating Navi (even though I'm a big fan of Navi) and VP beating ENCE.
Well technically the only upset would be VP beating ENCE. Astralis are very closely matched and even ranked higher than Navi. So not sure what you mean.