well, For one, the only reason they're bottom loading is the "NON" removable bug net. That being the case it is more difficult to maneuver the pad underneath you. Is it that big a deal? depends on who you ask. Personally, I rather not have to do that.

Second, as bmisf pointed out, they don't make good ground shelters. Of course, the argument could be made One could sleep on the netting to feed the fire, as spiritwalker pointed out. Again, personal taste, but I rather have a removable bug net.

Do these personal experiences prove they're troublesome? Maybe not to others, but to me they are reason enough not to own one again.