My experience with amember has been extremely positive. I've been using the product in a production environment for over 4 years.
I've never experienced deleted posts or whatnot so I can't really comment on that.
The software works as intended though if your forum is extremely 'hacked' then probably buyer beware. But that is the price to pay for ANY product you wish to integrate with a vB that is 'hacked' to death
Cheers,
~Regs.