Its a little scary the first few times you use it, but that's more of a user end issue.  The canner works well once you get the hang of it.  I would recommend getting the 3 piece weighted valve rocker and an extra seal gasket from the manufacturer.  The gauge is great, but with fewer and fewer places that will calibrate them, its better safe than sorry.  I've used it on a glass top stove with no issue.  And be warned - it is large and as such tends to be a space hog in storage.