I've implemented a migration from 7x to 2014.2 but that was for premise, not cloud. As it is browser based, performance and deployment is definitely much simpler (no more packaging of clients whatsoever, or playing around with connection profiles).
I'm based in NZ and during the days when HEAT Cloud was only hosted in the US I haven't had any issues with performance even during heavy configuration phases. I guess the only thing to keep wary of are the outages during upgrades - but obviously the flip side to that of course is that your system will always be upgraded with the latest version (prem vs saas situation). In saying that, HEAT communicates to their customers on future outages and for major releases you get the chance to sign up for a pilot instance prior to when staging gets upgraded giving you an early peek to new features, fixes, etc.
Hope this helps.