A tough question to answer. You'll find both opinions. Many will tell you you need to use the X all the time and many will tell you to just lead with the heel a tad and go straight up the hone and you'll be OK. I use both methods and find they work equally well however I gravitate towards the X mostly because most of my hones are narrow so I'm used to doing it that way. You just have to be a bit more careful if you go straight up the hone because you can more uneven wear.
Of course this gravitates into the next issue of whether you hone with one hand or two.
I've tried both methods and personnaly get much better results going straight up and back instead of the X pattern. I have one razor that was the exception as the spine had some very uneven honewear.
In the end the correct answer is which ever one works best for you.
X pattern, especially since all the razors I have are restored ebay junkers. You can work around anything but the worst warpage and/or smiles with an X pattn...just try that with straight passes!