I have had my Paragon Contempo Pop 6oz for several years now and I love it.
You do have to watch for kettle wear, as it will eventually happen (as there is a metal stirring rod which can and will scrap the bottom at times), but even after 6 or 7 years now that I have had mine, there is only some light scrapping marks in a few places, but nothing through the anodized coating. Really the thing you want to make sure you get is one that can be taken apart and parts replaced. Some of the cheaper ones do not have replaceable parts (i.e. power is hardwired to the kettle, no access to the stirring motor due to pop rivets, etc., etc.).
I can easily use the 8oz packs in this unit with very few unpopped kernels (or burnt ones as well). In fact, I havn't used 6oz pre-measured packs in years, since I found that I will typically eat all of the 8oz without problems (and in most cases will do 2). It cleans very simply with paper towels. I found it best to clean the pot while it is warm. You can simply turn it on for 20 seconds or so the next day (or even a couple days later if you really forgot), and wipe it out/down with dry paper towels. I use a wet paper towel on the glass surfaces followed by a dry one. The bottom tray easily lifts out and I wipe it down with some soapy water, rinse, and dry every once in a while (otherwise I just wipe it down).
Speaking of all this, I need to go get some more popcorn supplies. I used up the last of my popcorn packs a couple weeks ago and havn't had use of the machine since then (and I have been missing it since it is so much better than microwaved).
I have been very happy with the Megapop pre-packs. I have tried a few different ones, and this is the one I have liked the best. I am thinking of trying a few different ones again, since it was years ago that I tried out 4 or 5 different ones and settled on the Megapop at that time and have simply been buying it ever since.