I've got 3 X's, all running LP, 2 on stock ROMS and one on Apex 1.3. I never have lockups or reboots. I think it's related to a conflict of apps (that LP may be a part of), but with all the apps someone can install, it's pretty much impossible to troubleshoot, unless you're the LP developer and you have logs from a collection of phones to show what combination of apps causes the issue. I'm not saying that LP isn't involved in some of the cases, but I know that you can't make a blanket statement that LP causes reboots. I think it's related to broad collection of circumstances (apps) that some people have and some don't. It wouldn't surprise me to discover that certain apps cause a certain system related file to become corrupted, and even uninstalling that certain app still leaves the system file in a bad way.
Having said that, and loving LP, I still think a viable option is to try deleting LP and installing ADW. It may not have the same conflict. If that doesn't work, I'd go the factory reset route. One of my X's had a random reboot issue that started the first day it was purchased. I tried a number of things (deleting some of the lesser known apps that my son had installed on it) over the next 24 hours to no avail. After a factory reset, it has never rebooted since.