You may have better luck asking on the Vegetable Gardening forum.

I feel that better quality seeds can be had from a catalogue rather than a store. When growing different varieties of corn it is important to know which types cannot be grown in close proximity. A good tutorial on this subject can be found in the Johnnys catalogue, the use of which would be appropriate to your location as they are in Albion, Maine.

It is also good practise not to grow corn in the same place year after year. Hope you have room to rotate your crop.

According to the Burpee website, you chose a sugar enhanced variety so I am surprised it wasn't sweet. I'm a fan of Johnny's Seeds which has a website comparison of sugary enhanced corn varieties which shows comments on flavors. That's why I like a seed source like Johnny's which gives more information.
We don't grow corn anymore because the raccoons always knew it was ready the night before we did. I buy from local farmstands. But whenever flavor doesn't seem good enough, I suspect not enough fertility. Agway farm and feed stores have a great selection of seeds from several companies. Do you have one in your area?

Here is a link that might be useful: corn comparison