This was a real client, here is the transaction:

http://mastercoin-explorer.com/transactions/d9b69dddefcbec474a8d21fca1f03ac9212644444e6b99a95274a27b57f43b9d

And we've also dealt with multiple other clients through our website directly. Here are some of those transactions:

http://mastercoin-explorer.com/addresses/1HRE7U9XNPD8kJBCwm5Q1VAepz25GBXnVk

We even got 15 MSC directly from JR's giveaway for helping to spread the word:

http://mastercoin-explorer.com/transactions/54ed989d316b055893bb5b1f9ec2cd8955f8071ae897bd497bf5f62949ebdc11
https://bitcointalk.org/index.php?topic=272577.msg3123235#msg3123235

I'm not sure which negative feedback you are referring to, but we also had a successful public transaction on the forum using maxmint for escrow:

http://mastercoin-explorer.com/transactions/b2f7d89292ec531679a306420fec30ca0915e9f4605e6e5776a4b94f6dc107ba

So please like I've mentioned before if you have any concerns feel free to message us directly and we will answer any questions you may have. We are really trying to help Mastercoin succeed, especially considering the amount of MSC we own, and hope the MSC community will help us to facilitate growth for this great new cryptocurrency technology!