TL;DR You should do it today
I postponed updating to Meteor 1.6.1 for quite some time, thinking it’s going to break something and delay our deployment schedule.
Finally a week ago I did, because I wanted the updated version of dynamic imports. Now I wish I’d done it way sooner!
Not only did it go smoothly (with few edge case exceptions), but after updating, hot reloads are blazing fast! 
I mean, when updating to Meteor 1.4 or 1.5 I was happy to get my reloads down from 30s to 10s, but now I find myself staring at the screen with glassy eyes, drifting away while waiting for the reload to happen, when it has infact reloaded before I even switched to the browser window!
It’s that fast.
I’m not sure if the improvement is as remarkable for everybody, but I highly recommend you update today and see for yourself, just to improve your life quality big time!