So, I'm on the TrainerRoad website and...wow...talk about pseudoscience.
I've owned make 12-15 different trainers and rollers over the years. Most were top name brands with which we are all familiar. I've also used 3 different track SRM units, 1 road PowerTap, and 3 different CycleOps spin bikes with Power Meters attached.
There is no dang way that this product does what they say it does.
One quick way to refute this: If you look at a basic mag trainer (that they support), it's actuated by a simple cable that is similar to a derailleur cable. This moves the magnetic unit closer or further away providing more or less resistance. They literally provide a chart stating that click #1 provides this power curve and click #2 provides that power curve. If you examine the mag trainer, you'll see how much adjustment range is in play. It's nowhere near being precise. Not to mention tire pressure or how tight you press the resistance unit up against the tire which deforms it.
What happens when your adjuster barrel is twisted more or less??
Save your money.
You'll be better off working off of RPE or Heart Rate. Seriously...avoid this product if numbers are important to you at all.
If you will pay them to give you power readings, hell, send me $5/workout and I'll mail you a piece of paper with a custom hand-drawn chart of what your power readings were for that workout
EDIT:
It seems that this company (as with many others) are capitalizing on the phrase "Power Meter" in order to make money. "Everybody uses power meters." + "Everybody says I need a power meter." = Being taken advantage of by companies.
EDIT 2:
Because the "science" behind their charts is so loosey-goosey, there is no reliable way to compare data from Trainer A to Trainer B reliably. The best one can do is simply relate things to the same trainer. "I did this effort on click 2 of my ABC trainer for this long..."