I'll throw my two cents in:
Tier 1:
Mercedes and Ferrari: Merc will undoubtedly continue to be the benchmark of the field, but Ferrari with Seb will be breathing on their necks the whole time, so will Kimi when he's in form.
Tier 2:
Williams, Toro Rosso, Force India, Haas: The Merc engines will help the Williams and Force India's out very well with Force India being the better overall car over Williams, Toro Rosso should outclass Red Bull bar anything going wrong with the 2015 Ferrari PU and Haas with their resources and Ferrari link will surprise come Bahrain at the lastest.
Tier 2.5:
McLaren: They'll start out better than the MP4-30, but will be in and out of the lower to mid points range for the first part of the season. Following some upgrades and some feedback work from Jenson and Fernando should see them in the points consistently and battling for Top 5's after Silverstone.
Tier 3:
Manor, Red Bull, Renault: Points will be on the cards, but it'll be a trying year for the once dominant Red Bull squad, so to the Renault/Enstone team after a tumultuous late and post season. Manor will be the big improver of the year with newly acquired staff and Merc PU. Watch out for them.
Tier 4:
Sauber: Unfortunately for Sauber, they'll steep further down the order in 2016. Lack of funds and raw hard driving talent apart from Nasr are going to have them struggle all year for many points. Sad considering with BMW and Kubica they were nearly the next big thing. What a shame.
I hope I don't look back at this post with bitter resentment for how the season's gone!

Friendship with Honda ended, Renault is my new (and more reliable) friend.