Bought the "Chef'sChoice Trizor XV EdgeSelect Professional Electric Knife Sharpener with 100-Percent Diamond Abrasives and Precision Angle Guides for Straight Edge and Serrated Knives, 3-stage, Gray".

It took some time sharpening about 9 or 10 knives, about 1/2 hour or more.

Just tried my Wusthof knife today cutting a pork loin into cubes for Pork Carne Guisada tomorrow.
Was a world of difference.
Had been just using a sharpening rod, that never seemed to do much.

For all the time I've had it, I was never happy with this Wusthof knife.  Wasn't any better than my 40+ year old Chicago Cutlery knives.
However, I love my Wusthof Brisket knife.
My Chicago Cutlery knives have improved greatly as well.

I think the key is changing the angle.
From what I read, most knives come with a 30 degree angle.  The sharpener changes it to 15 degrees.
That is the reason it took so long to sharpen all of them.  Will be quicker now.

Don't know why it took me so long to buy a sharpener.   

I have a white one, not sure of the model, it is probably 20 years old or close to it, it has 2 diamond discs and a felt one I believe. I have not used it in a while. I used to get it out and sharpen every knife I had then put it away. The knives would stay decent for quite a while with a few strokes through a little ceramic sharpener followed by the diamond or ceramic rod.

I like it and some of my cheap knives really need it again. most of what I use now seem to do well with the ceramic draw through followed by the ceramic rod.

I think you will really like it.

Sounds like the same one I have. 3rd slot is for polishing,

I think the key is changing the angle.
From what I read, most knives come with a 30 degree angle.  The sharpener changes it to 15 degrees.

Wüsthof sharpens some of their Kitchen knives at a 14-degree angle and others at 18-degrees.  So it’s hard to determine the angle that disappointed you.

I hope that your chosen 15-degree angle provides the performance you’re looking for.

When reading about knife edge angles, it's important to note if the author is addressing the grind angle or the knife edge total angle.  A 15-degree grind produces a 30-degree total angle.

Under 10-Degree Angles
The lowest angles are suitable for edges that are used for cutting extremely soft materials.  The edges are not subject to abuse so the lower angle can be maintained without damage or edge failure.  Think straight razor.

10 to 17-Degree Angles
A sharpening angle of 10 to 17-degrees is still quite low for most knives.  With a total angle of 20 to 34-degrees, this is a very fine edge that is typically too weak for any knife that might be used in any type of chopping motion.  Also, harder knife steels are are more brittle so they're more susceptible to impact damage.  If your knife is used for cutting soft items or slicing meats, this lower angle can hold up and provide a very smooth cutting action.

17 to 22-Degree Angles
A 17 to 20-degree angle is best for most kitchen knives.  Some knives (typically Japanese knives) are sharpened to ≈17-degrees.  Most western knives are ≈20-degrees.  These angles are usually not durable as rougher treatment in harder materials will turn the edge if it’s a total angle under 40-degrees.

22 to 30-Degree Angles
In this range, the knife edges are considerably more durable.  A pocket knife or a hunting knife will inevitably see abuse not seen by knives meant primarily for use on softer materials.  While the edge may not ultimately cut as well (but you may not notice a difference) it will be significantly more durable.

Over 30-Degrees Angles
Any edged tool that is sharpened past 30-degrees will be very durable, but its cutting ability will be noticeably reduced.  This durability has an advantage because more force can be used to make cuts.  While many knives won’t benefit from this sharpening angle, a machete, cleaver or axe will.

An 18 to 25-degree edge is a good choice for the average cook.  I recommend starting high and working toward more extreme angles after judging a knife's performance.

Just my 

Those are the kind of reasons why I stay away from buying expensive knives.  While that information is most likely extremely helpful for many, it is more than I care to learn about knives.  I greatly appreciate Paul sharing his knowledge here so don't get me wrong about that.  When my cheap restaurant depot grade knife gets dull and no longer sharpens in my not very expensive manual knife sharpener, I through it out and get a new one.

 I just bought two, one for each daughter - for Christmas.. Neither of them or their spouses have any idea on how to sharpen knives. Kind of ironic as both are excellent cooks.