We have been as happy

with Nexternal for our merchant account as we have been with FutureQest with our hosting. Nexternal communicates very quickly via email and telephone, resolves problems very quickly and has a flexible system. For example, you would be able to show each of your t-shirts with each of the designs to any customer who wanted to see what they were actually buying and price each size or design differently withour setting up duplicate item numbers. They have full integration with UPS and Paymentech and a number of other providers. It is pricey but the time we spent either working around other merchant account problems or not being able to do what we needed did not make up for a cheaper price. If you want to see how it works, go to our site
http://www.seeetch.com , enter the store and go to the Just Personalized department.
Also, the stats provided are useful and I am not aware of any downtime for the four months we have been with them.
Downside is that you can chew up a lot of time online entering data and changing item descriptions can be time consuming.
Hope that helps. if you have any questions, let me know.
Chilihorse (a very cold and wet horse he is today!)