Waterpik Complete Care 5.5 Water Flosser 5.0 vs 7.0 Which one Better more Reliable ? Question HD

Can someone help me with this, I want the more stronger reliable Improved version! Are both the 5.0/5.5 and 7.0 the same quality and water pressure?? Or is the 7.0 WP-952 built better?? I bought it for $116.96 + 13%tax and 10%discount = (Total $118.94 CAD / $91.25 USD)