All of the main grinders are good and they all do the same thing, spin a sharp stone or wheel variant for you to rub your metal tools against.
The first grinder I purchased was the cheap 6 inch white wheel grinder from Record, added to it the Robert Sorby universal jig which is great if you want a long grind ( you don't need a long grind but it is useful and what I prefer).
Having tried most if not all of the grinding systems on the market, slow systems and jigs etc I can say that they are all good, I do prefer the Robert Sorby Universal jig though, but are the slow luxury grinders worth the money. ?
I still have my original Record 6 inch wheel grinder and universal jig.
You need a sharp edge, that goes without saying.
You get a sharp edge with a white wheel, you will get a sharper edge with a CBN or slow grinder with a honing system.
The sharper the edge the finer the cut, the finer the edge the faster you will lose this , a sharp tool edge has to be finer and thus will blunt quicker, especially when roughing out with bark, grit and all the other stuff that is on the outside of a log.
99% of woodturning is removing waste wood and as long as this is done efficiently with a sharp tool (with good geometry, which is obtained from using a good jig, or home made one), then the last 1%/finishing cuts are the most important. Just use a freshly sharpened tool for finishing.
My prefered finishing tool kept purely for finishing is a traditional grind 10mm bowl gouge, as this gives an exceptional finish due to the amount of cutting edge and bevel support.
There is no doubt from trying them that the more luxury grinding systems are very good. The Tormek is often reported as being slow, I would say to this that it is not designed to remove metal from the tool quickly, but to apply a sharp edge to it with good geometry, this it does extremely well.
I sharpen my main tools on a standard 6 inch white wheel, and hone my finishing tools on an 8 inch disc of MDF to which I have stuck 600 grit abrasive. This has a spigot on the back to fit into the chuck of my lathe. I use this for sharpening the finishing gouge.
So in answer to your question.
They are all good, but do you get £400 worth of better turning from them, in my opinion no. A good geometry and a sharp edge and correct tool presentation is pretty much all you need and you can get this with a standard white wheel and jig.
I keep thinking about buying a slow system with Gucci diamond wheel, but always end up spending the money on wood or taking my children out for the day instead.
But if I had the spare cash yes I would have one, just like I would have a Ferrari too if I could afford it.
