I've been doing a lot of homework comparing machines and I'm leaning strongly toward getting the Gazelle (BossKut).
There seems to be a substantial difference between the Silhouette and the Gazelle, one difference being that the Silhouette is reported to not be able cut materials (think: thicker, heavier weight materials that DP or lightweight cardstock) that the Gazelle can cut.
I've read a lot of user questions and comments made about both machines on forums and by far those using the Silhouette sound like they have more problems using the machine than do Gazelle users.
I just got done watching all of 21 youtube tutorials uploaded by a BossKut rep on the Gazelle and the tutorials are wonderful: (this link will get you started on watching those):
Boss Kut Gazelle NEW Print & Cut Demo.mp4 - YouTube