My first post here! Looks like this is currently on sale, not the lowest ever but still a decent deal. RRP $149. Other colours available.
I bought it in late March for $88 on Amazon AU. At the moment it's starts from $91 on the local Amazon (depending on the colour / theme), which is probably a better deal, especially if you have Prime.
Any idea if this is any better than fitbit ace 3?
No idea, sorry. I've only had experience with vivofit jr 2 and 3. The Garmin app is great.
You can check this comparison review between this and the Fitbit.