It sounds good but I also have some huge concerns.
I'll address your concerns one at a time.
You ripped off the bitmixer design/code, this is also what all the ripoff mixing sites do. So you seem like one of the guys who have been scamming the bitcoin community for years. Maybe your service now is legit, maybe your former services/sites werent. But there isnt much trust here for me when you are basically a scammer who now trys a legit service because obviously as others have stated at some point, or on some (big) transactions you would rip people off.
Why did we use Bitmixer front end? Well first ask yourself how many people have used Bitmixer? A lot. How many people on day one know how to use PrivCoin? A lot. How much do we now have to spend on educating users? Zero. Furthermore, none of our other services purport to be in the Bitcoin business because they aren't. We all accept Bitcoin as a payment method for example on a popular Fan-site for microtransactions. We also own some privacy related services.
Secondly, we don't permit as you say "big" transactions. Try setting up a Bitcoin mix, there are hard limits. We do not want to be a high volume Bitcoin mixer for reasons we don't disclose.
Also many of your posts are EXTREMELY alarming. Like you say stuff as "we did something wrong when we ever get a support email". Yeah right. People always make mistakes and will need customer support.
Ask yourself how often you have to call up Google because their search platform doesn't work? I'll bet you've never had to. That's doesn't mean we won't respond promptly to emails, it's saying our application works so well that nobody will have to email us.
Also you do react quite unfriendly and pissed at critique which often is a sign for a bad character person.
There was exactly one unfriendly reaction to somebody who said something so outrageous it's outrageous. If you were a technology person you'd understand so allow me to metaphor it for you.
Imagine you go to a new car dealership and you sit in the driver's seat of a brand new car. Without turning the car on or moving at all, you say to the salesman "this car doesn't go over 100 Miles/Kilometers per hour". The salesman then turns and looks at you and says "Yes it does, why would you say that without even trying to drive?"
The person above did not try to use PrivCoin with NoScript because if he did then he would see that it works. This means he's either lying (if he tried NoScript), or he's an asshole (for not even trying the site with NoScript). There are no other options.
A cursory forum search of his post history reveals:
1)
https://bitcointalksearch.org/topic/m.222240322)
https://bitcointalksearch.org/topic/m.222260663)
https://bitcointalksearch.org/topic/m.22244990He's trashing the threads of all the competitors for the signature campaign he belongs to without merit.