I have a 4X and my wife has an LT1, so I have ridden both.
I did not like the LT much with a 5 inch fork, and my wife was complaining that it felt sketchy. So we put a 6 inch fork on it and it has improved it a fair bit. It went from a 69D head angle to a 67 which is much better for the trails she rides.
My 4X has a Marz 44 RC3 Ti on it and it gives it a 67D head angle as well, except the bike is lower and has a bit less travel than the LT. I still much prefer the 4X as it corners better and is just more playful. It is heavier though, and does not pedal as well due to the slack seat angle and extra weight. But for going downhill, the 4X is a really fun ride. It corners like crazy and feels very stable jumping. It's tough enough for probably anything you'd care to hit with a 5 inch bike and then some. I've been pounding mine for 6 years and it's still going strong. I believe the head and down tube are the same as a VP Free, so it's built for abuse. I run a DHX coil on mine and with the coil fork up front it feels like a mini DH bike.
Personally, I would take the 4X over and LT1, but cannot comment on the LT2