I have tried most of the devices, and used a Fitbit One for a couple of months with no regrets. However, I tried the Charge and returned it because of severe scratching and sleep monitoring failures.
I've had the Band since it was released, wear it 24/7 ( except for short intervals for charging ) and I'm very satisfied. At first, it will feel different because of the size, but I quickly found that was not an issue. It has been very rugged and I wear it while working outside. The screen protector they provided has worked perfectly ... not a mark on it.
I do a lot of pre-release testing on products, so being an early adopter was not an issue. I know the software will improve and I'm excited to see where it heads.
Because I have a Windows Phone, I really like the integration and notification. It helps since I often don't hear my phone when it is in my pocket and now I'm notified with a vibration on my wrist that I always feel when a call arrives. It's also nice to use the Cortana integration for quick info, and to schedule reminders.
I'd love to see how you feel about it after 2 weeks.