I use spacebags too. There great for socks and underwear. I find that they leave t-shirts and the like kind of wrinkled. For dress clothes it is good to leave them in the dry cleaners bags to orevent wrinkling. We've gotten pretty good a weight guessing too. I usually try to find a counter at the airport that is unmanned to give them all a quick weight test so I wont have to hold up the line repacking if one is over. I've only had one go over once (by a pound and a half) and I simply stuffed some of it in my carry-on which is always pretty empty.