Are you part of Mercury developer team or associated with their team in any way?
Some people here are allergic to Newbie members, so I think that some small explanation would be nice from you.
Yes, I am part of the team.
https://github.com/tomt1664There are mixing services that don't charge any fees, and I think that you should consider lowering your fees during beta phase and increase them later.
I would also like to see some code audit and reviews from other security experts.
We have to charge some fees (we are a business). We are certainly not planning on generating significant income during beta testing, but there is a minimum amount that can be charged. Anything less than 0.4% of 0.001 BTC hits the dust limit.
Once beta is passed with the current design, we plan on adding a feature to allow users to pay the fee via Lightning. This could be made lower.
Professional code audits are expensive, and I think we would need to see some success before paying someone to do this. More likely we will have a bug bounty. Hopefully the code will get more attention as it becomes more widely known - all development is being done out in the open, and has been from the start.