There’s no right or wrong answer to this question which might mean this question gets closed. But you should research this elsewhere as its already been widely debated on blogs online – for and against, pros and cons.
That aside, you need to decide what the purpose of using a framework is – for YOU.
As my purpose(s) may differ from yours as we all have different needs be it business, client or personally related. I’ve used Roots and I like it because it fits some of my needs but not all. Same for Bones. Although I preferred Roots, if for nothing else for the simple reason that I’ve used it more.
That’s a subjective opinion and that’s what you’re going to find a lot of elsewhere too, a tit for tat style conversation over frameworks for the most part.
Both are built and based off the HTML5 Boilerplate with the exception that Roots also is based off Bootstrap from Twitter.
Since you’ve narrowed it down to two frameworks, you should decide what is it about the two feature sets you like, don’t like and wish the other maybe had. Through this process you’d be able to easily eliminate one or the other. Or quite simply see that there’s not an overarching difference between the two where you’ll fare better or worse.
Instead you should decide whether using a particular framework of any kind is going to suit your individual needs and business purpose. Whether or not the framework allows you to achieve x whatever x may-be and same for y and z and etc etc. You get the idea.
For me I am always looking to see whether I can achieve more efficiency in my developing by removing more repetitive tasks speeding up the process of developing sites for clients.
So out of the box support for features I use on a regular basis is important to me and removing the unnecessary, constant repetition is above all the most important so I can focus on solving the real project problems at hand, not only that deliver projects faster, get paid faster and in most cases complete more projects as a result of this efficiency.
I don’t like Gensis which is in my opinion an abstraction of an already existing and powerful WordPress API – I don’t want to learn someone else’s hook this and hook that because that slows me down. If that works for you then press on…
As you can see its very much a personal thing and if you let one persons opinion sway you over another then you could be wasting your time as you’d be using something based on an opinion that may not match your use-case and that’s bad, maybe 😉