Combination stones are always partly a great idea and partly a compromise. There’s no question that individual stones work a bit better than the flip-over versions, but with a two-sided double grit stone you get convenience and speed. No matter which stone system you choose, if you own Global cutlery, you need matching Global sharpening stones. The specially ground thin bevel of the hard cutting edge could be ruined by an ordinary honing steel or a sharpening machine.
With this combination stone, you get a rubber base to prevent skidding on the work surface — also eliminating scratching the counter or tabletop if you keep the base clean. A short fifteen-minute soak in water provides enough lubricant for the average sharpening task, and a little water in the basin of the holder keeps one surface wet while the other is in use. With the 500 grit coarse side, nicks and chips can be gradually overcome, restoring the original long bevel to its correct shape. With the 1000 grit medium side, hone the bevel into a very serviceable cutting edge.
For the finest edge, equivalent to the new edge set at the factory, you will need another stone in fine 5000 grit. That gives a high polish to the shaped and refined bevel you get from the combination stone. Without the fine stone, you get an edge that works great. The last fine polishing step gives you a knife edge that’s even a little scary.
One limitation of the combination stone is that you can’t use the coarse side to grind the medium stone level again if you wear a hollow in the surface. Resurfacing requires another stone. Be sure to work with all parts of the abrasive to keep the wear even.