You might want to consider mounting your X-Monitor where it can easily be seen with just a glance. I find the A-pillar mount to be pretty good.
Since the X-Monitor has a constantly changing digital readout, you have to concentrate on looking at the numbers a bit more than the analog guages. You get to know where the needle, on the analog guage, is supposed to be and a slight glance will give you the info. that you need.
I would think that if you mount the X-Monitor in the cubby hole you will have to "dramatically" take your eyes off the road to read the info. you want. When you are running hard (racing or towing heavy), that's when you need your guages the most. That's when you want to be watching the road the most.
I chose my X-Monitor because you could get a number of readings in a small area and still keep the grab handle, which, I use all the time.
These are a few of my thoughts on the subject and I hope they might help you in your decision
Joe F. (Buffalo)