Dear Jeffrey,
Your on the right path. I too started out with epson transfer papers. They are simply very durable, but they are a pain in the rear to apply. I believe they were designed for the novice in mind. Hence they were designed for the 'ole household iron. They work very well with an iron. If you're using a heat press they're a little more difficult to apply.
In the world of the transparent transfer, which was meant for light fabrics, which epson papers are, there are hot peels, and cold peels and some papers even are both (you can peel them hot or cold). Now to bring you to school, when peeling a transfer while it's hot it will leave you a matte finish. When peeling a transfer paper, that is meant to be peeled after it has cooled down, hence the name 'cold peel', that my friend will leave you with a more of a sheened finish. So choose your paper with that in mind. Papers should always be advertised as either or. Now when I say take you to school I do not mean to offend. I've been taken to school many times since I began in this transfer world. A great mentor has been the guys at Alpha Supply. Not only are they friendly people and very knowing they also have a website to boot. Here's the link,
Alpha Heat Transfer Paper for White and Colored Fabrics. If this link doesn't work just click
Heat transfer paper, tutorials and heat presses to start a business and go to their heat transfer page. After you master what the heat transfer is all about and the different forms they come in, then you can start thinking about which printers to use (laser vs. inkjet), which ink systems to use (ie. cis systems), what kind of heat press(es) you want to play with (swing aways or clam shells), then you can play with Roland cutters. These little beauties will cut away most of your excess transfer that you don't want showing up on your final work. The list goes on.
I guess to answer your question, I would consider epson papers to be the best of their kind. Their kind not being professional grade. Simply because most pros don't use this kind of paper. I believe that they are indeed a pain to apply with a heat press. But their washability is great and they have lasted to this day. The only thing is that with an iron you can not maintain consistancy in your final product.
In conclusion, for now you are ok using these kinds of papers (avery, epson etc.) I wouldn't build a business on them. In the future or even now you'll need a transfer that has a reputation and one that you will like. One that you can say, "hey, that is some good peelin' " Try the sofstretch transfers, now that is some good peellin'
-Marc