I'm looking for a bike under $400

[singhd]

I'm looking to buy one of the following bikes. Which one is the best?

1) Ironhorse Estate:
Ironhorse Estate Front Suspension Mountain Bike Adult - SportChek.ca

2) K2 Trailhead Light:
K2 Trailhead Light Front Suspension Mountain Bike Adult - SportChek.ca

3) Trek 820:
Trek Bikes | Bikes | Mountain Hardtail | 820

4) Norco Scorcher:
Norco Bikes Bikes Mountain Bikes Adventure Scorcher

5) Norco Pinnacle:
Norco Bikes Bikes Mountain Bikes Adventure Pinnacle

6) GT Aggressor:
GT Bicycles | G10AGR26 - Aggressor