My SB is the best mod I ever got! I got mine from electronic-cigz last year. It fell out of my pocket last year when getting out of the truck. It laid in the street until lunch when I could get back to it. Was run over a few times as it was pushed down in to the snow and ice. Chiseled it out with my boot, blew off the snow and hit the button and heard a sizzle! I replaced the atty and cart any ways but it still works like a champ.
As for the LTVV I just got one a couple of weeks ago and mine has the vent hole on the bottom cap but I got mine from cdnvapor. I've never had a problem with under/over charging any batteries. Also my LTVV flashes the LCD screen when the bat is dead and won't fire so I'm not to worried about it. I also don't go above 4.5v.