I have been with coinjar for a couple of weeks now and my only issue I have had is the signing up issue. I provided the relevant docs and then after I had sent my first payment I was required to send more and more documents, which is fair enough but they could have requested all the selfies etc on the initial sign up process instead of dragging it out as bitcoin went up hour by hour. Another issue was after the first payment was approved the second was held pending for several day, ( christmas and bank holiday apparently) and after another support request I found out it was because I use a vpn, that could perhaps be something that is flagged up during the sign in process also. Apart from that the support has been helpful. and my latest payment has gone through quickly, although now bitcoin appears to be on a downward trend again. I haven't tried selling anything yet, so cannot comment on how easy or expensive that is, and have not tried to transfer money back into my bank account. But overall apart from the initial problems it seems a fairly easy system to use.