I have the Burton Casas and like them just fine. I have about 14 days on them and they look almost new. My boots are about one half size too big, so I actually do get some heel lift in them. For the first two or three days, they were very tight around the tops of my feet but they have since loosened up significantly. This is common - expect your liners to loosen up a bit after you've broken them in.
Try wearing the boots around the store for a while to determine how well they fit your foot. Any discomfort will greatly magnify once you get to the slopes, so try on as many boots as you can just just pick the most comfortable one.