Recent news from Android Central has shown that the bootloader on the Droid X is locked. For the average consumer, this won't be an issue. However, for some of the more tech savvy users who like to root their device and flash custom ROMs, well this certainly becomes an issue. Custom ROMs can provide early updates to newer Android versions. They can also provide extra functions and remove added bloat-ware, often found pre-installed on Android devices.
The bootloader may be locked, but that does not mean that root access will not be attainable. There are two phones which come to mind that are in the same boat. The Motorola Milestone and Sony Xperia x10. Both devices have been hacked to obtain root access, but both devices have locked bootloaders preventing custom ROMs. With generic root access, users can still uninstall some of the unwanted bloatware and install special apps from the marketplace which require root access. Some popular examples are SetCPU and WiFi tethering.
Are you still interested in grabbing a Droid X?