The main difference between those two guns is the stock, I would get the full stock if i had to chose between those two. Airsoft under-fold AK stocks are usually quite flimsy, easily broken and are generally terrible to cheek.
I'm going to agree with cetane and say you're much better off spending a little extra now for a metal bodied gun.
It's difficult to predict with any accuracy the longevity of either of those guns. So much depends on the use, also less expensive guns tend to have a higher lemon rate. In my experience the Echo 1 would be the better choice for durability though you'll probably find people who will argue either way based on their own experiences. The good news is AK's have a V3 gearbox which are "easier" to work on than most.
Last edited by Kozzie; October 7th, 2013 at 20:31..