If you prefer, there is a quicker way to get into recovery.The unit doesn't have to be plugged in. Follow the steps below and you will be able to get into the Recovery mode for factory restore w/data wipe.
If your tablet is on, power it off.
Press and hold Power until the device powers on, then immediately press and hold Volume Down (while still pressing Power). You will see the word Start with an arrow drawn around it.
Press Volume Down twice to designate Recovery mode.
Press Power to restart into Recovery mode. You will see an image of an Android robot with a red exclamation mark.
While holding down Power, press Volume Up. (just press it once and let go)
Use the volume keys to scroll to "wipe data/factory reset" and press Power to select it.
Scroll down to "Yes - erase all user data" and press Power to select it.
If you have issues getting this process to work send me an email at cl-fred@asus.com and I'll be more then happy to help you with it.
I have had three Nexus 7 2013 devices get stuck at the X so far and all have had the "Process com.google.process.gapps Has Stopped" error loop as well even though the download manager was enabled. I factory reset and all is well for a while only to repeat from a few days to a week later. Called Google and tech agreed something either up with 4.3 or ASUS is pumping out shoddy hardware. Looking forward to a Google response as resetting my devices every few days/weeks is not a solution.
My Nexus 2013 also have this stuck-at-x problem. I need to perform "wipe data/factory reset" in recovery mode every few days. Also, Chrome or Email will report that it had stopped working right after powering up once a while. I need to delete Chrome/Email and reinstall it to fix the problem. Hope Google/Asus will fix the problem soon so that I don't need to return the unit.