Glass vacpots in are lovely to look at, fun to watch brewing, may burp near-boiling glops of coffee grounds on the stove, are fragile and the narrow-neck types are hard to clean without the right bottle brush. I have about a dozen vacpots and favor the stainless steel antiques (with metal filter disks) or wide-necked glass versions (with glass rod filter) for regular use. These are discontinued brewers found on ebay. If you use a glass rod or metal disk filter, grind quality will be an issue; if cloth or fine metal screen filter then grind quality is less critical.
One can debate if they make coffee any better than a press or not. I can't say.
Theory of vacpot goodness rests on the idea that, by the time brew water makes it into the north pot, the brewing temp is the perfect 195-205* range.
More at:
http://baharris.org/coffee/VacuumCoffeePots.htm and
http://home.planet.nl/~rjeroenv/links.html#7a