I apologize for bumping...
My 1p worth. Personal opinion only. A belt grinder is worth the money only if you make tools (which I do). I do not own one of the machines that started the thread. I simply clamp a secondhand DIY belt sander ($10 at a thrift store, Makita at that) in a Workmate at a convenient angle, and have at it. Reason is, a belt grinder removes a whole lot of metal in very little time. Of course the amount you remove in a given time depends on the grit of the belt, and a wide variety of grits is available mass-market. I do recommend weighting down the Workmate. It tends to wander around the floor if you don't. I use really hefty birch logs. The best Workmates are the British pre-Black and Decker variety, they were much better made than the current crop of B&D plastic junk. I think that our models, the real bodgers of the 18th and 19th centuries, would have killed for a Workmate. I know, they are not bodgerlike, but neither are mootorised grinders, either. If you wish to sharpen as opposed to make, why a file is your best friend. Lacking a Workmate, clamp the belt sander in a big heavy vise. Oops, vice. So I personally would buy a really cheap belt sander, DIY store variety, and clamp it in a Workmate, and I would not spend my hard-earned Pounds, shillings and pence on a commercial grinder. I would gladly shell out the dollars or quid for a pre-Black and Decker Workmate, made in the UK and not in the USA or China. And I would find a secondhand belt grinder. Presto, stationary belt sander. Good enough for all bodger purposes. I find the disk sanders on the commercial machines useless. Unless you are making wooden clocks, which I am doing at the moment. But that is a most unbodgerlike activity, way off-topic.
Now here is what I consider the theory of the thing. If you are making a tool, there are several stages. Just so as we know where we are, suppose we are making a knife. First we have to cut it out to shape. Off topic. Then we have to rough out the edge. It is here where the belt sander excels. You need to remove a whole lot of metal in a very short time. In other words, rough it out. Do it on the belt sander. Then probably you want to heat treat your knife, again off topic. Then you have to refine the edge. For this I think the wet grinder is the thing. Lots of stuff on this board on that subject! Finally you have to hone it and for this I use in succesion diamond hones and Japanese Waterstones. By hand. There is no better way to get a good edge on a knife. For an axe I might use the belt sander once. To get the bevels where I want them, usually a lot less than the 45 deg a store-bought axe has. After that I file, and use a hone to get the final edge. So at each stage of toolmaking, you remove less and less material. Belt sander just one stage in a process. If I had to spend my money on a power tool to grind axes or adzes or knives I would spend it on a wet grinder. Indeed that is what I did. I can improvise the belt grinder.
BTW a note on the "Clarke" brand name (It applies to many another brand name). In spite of its seemingly British name the thing is actually made in China. It has been, as they say, "rebadged", no doubt from Rong Fu to Clarke. Not making that up, Rong Fu is an actual Chinese toolmaker. Not that many of them, as it turns out. They are rebadged under many names. In the UK, Warco and Chester come to mind. In the US, Grizzly and Harbor Freight. I happen to own a Clarke small (6cm) pillar drill. It has been completely satisfactory. But what I find with these Chinese tools is that they are a bit spotty. One day they are right on the money but next day something slipped and the tools made that day lacked something. Maybe they forgot to heat-treat some important part.So the tool is junk. It is roulette. I do not denigrate the Chinese. They are doing in a decade what it took us all one hundred years to discover. I do not blame them if they slip up sometimes. I blame myself for not checking the thing out thoroughly.
Usually apologize for a very long post like this one, but not this time.