RT-AC68U Dual wan question

I am looking at buying the RT-AC68U, largely because of the dual wan support.


I have 2 ISP providers, one fast, one a bit on the slow side.

I work from home, so I have the slow one largely for a backup. Either ISP would get the job done.

I just wanted to ask what is your experience with dual wan support for load balancing.

Thanks
Michael