Ok, i wasn't going to, but here we go......
Lets start with the simple stuff - Survival.
Predators are not designed to be extreme survivors as the aliens are. Can predators survive in the vacume of space without air? No. Can predators survive in deep cold without the aid of technology? No. Are predators as efficent hunting without their tech than with it? No. Are predators bound by the rule of 'survival of the fittest?' No.
All of the above are just minor statments i have chosen when it comes to weaknessess of the yujita, i don't want to go into extreme depths here as i could be typing all day.
The aliens are bred to be the most lethal killing machines in the universe, the predator culture acknowledges this which is why they make it their goal to be able to hunt the xenomorphs - to show their pride and determination and prowess as trained hunters.
Aliens do have weaknesses but in my opinion, not ones that are of much relavance. Perhaps the biggest weakness is that the aliens do need hosts in order to populate their kind and reproduce the species. Also as mentioned earlier - fre is an issue with the aliens, they are afraid of it, but there has been no case to date of an alien fatality from the use of flame based weaponry.
Intelligence of the species is of course lower in comparrison to the predator race, as they are a cultured species with intellect enough for space travel and hi-tech weaponry, but in effect, the xenomorphs are fast learners with capacity to formulate flanking plans and strategic ambush patterns in order to trap their prey.
Without being bias, (as i like to give both species a fair chance despite my love for the aliens) i do beleive that the predators possess more valid weakness points for exploitation than the xenomorphs.
TBC......
www.thorndesigns.netdarkness of acheronBugRenders