Just installed this today and used it for one test order.I noticed something odd.
1. The weight was correct when I printed the label but now in the "Printed" it shows that the package went from 3oz to 2,685.0lbs! and is accompanied by a red x.
2. I noticed that it correctly updated my orders' status to DELIVERED however, it left a message like this (with a Customer Notified X):
Code:
Shipped on 02/16/2011 via USPS [USPS First Class], Tracking number 9101010520000000000000
Would it be possible to have Stamps.com add this before the tracking no.?
... so it would update zen-cart with (easy clicking for a customer viewing their order status):
Code:
Shipped on 02/16/2011 via USPS [USPS First Class], Tracking number http://trkcnfrm1.smi.usps.com/PTSInternetWeb/InterLabelInquiry.do?origTrackNum=9101010520000000000000
*last 13 digits of the tracking number was replaced by zero's on purpose. 
Other than those two things... It looks like I will have to bag my Brother QL-570 as it isn't compatible with Stamps.com. *Looking into the 4 label sheets (SDC-4100) - Or even maybe those fancy labels where half the sheet is the shipping label and the other half is the packing slip like Amazon does with the book boxes. hmmm