I just bought a Global knife (GF-33) and the literature that came with it suggests using a ceramic honing "steel" rather than a steel one. Apparently steel could be too abrasive for the type of metal Global uses. First of all, does this assertion have any merit? If so, I was looking at the rod that Global offers and it is one hundred dollars plus! I noticed that other brands run much much cheaper. Why such the big difference? Are all ceramic rods created equally? I just want to buy a thirty dollar one if it's all the same. What have other people done for their Global knives?
I can't speak to Global knives specifically, but my local knife sharpening specialist recommends maintaining newly sharpened knives with a ceramic honing tool instead of stainless, saying "A metal steel may be too aggressive in the first couple of months after I've sharpened your knives and can cause more harm than good." I haven't tried it, but basically I just don't seem to need to use the conventional honing steel that I have much until it's been a couple of months anyway. Ceramic should be somewhat less hard than steel, and it may be less likely that you'll apply so much force as to bend the edge too extremely if you're using something that is slightly less hard than the material of your knife.
The one that my local knife sharpener offers has a rubber tip on one end, which I could see providing stability if you keep the edge on the counter; a wet cloth could stand in for that. I'm not sure what other differentiating features a typical ceramic steel offers, but I didn't see many with the rubber tip feature. Why is Global's more expensive than others you looked at? If there are no features with obvious value, then the answer to why they charge more is probably "because they can."
Polished steel honing rods have no teeth and are less abrasive than ceramic "honing" rods. There are some types of steel rod that are abrasive. They have grooves cut down the length of the rod, sometimes in a shallow spiral and sometimes cut right down the length. These rods will hone a knife, but they will also shave off an amount of steel.
If you want a rod that you will use as regularly as you use your knife, you should go with a polished steel since the others will gradually change the shape and angle of your blade.
I've no experience with Global knives, but it's difficult to imagine that this advice does not apply.
The material of the honing rod (called a steel in the UK) doesn't matter, it is the cut that matters. Most of the sharpeners that come with knife sets are coarse or medium cut, meaning that the ribbing on them is very aggressive and will take off lots of metal when used. If you use a coarse or medium rod on a professionally sharpened knife you'll actually dull it. What you need is a fine or extra fine rod whatever the material of the rod. Ceramic ones are very expensive, steel ones are much cheaper and IMHO just as good.
I bought mine from an online butcher supply store, there's plenty to chose from. Butcher supply stores also have extra-long rods available, and I find that long ones are much easier to use.
I own several Global knives and use a generic ceramic honing rod, which was a lot cheaper than Global's own rod and works perfectly. Remember, you pay for the Global design as well.
Also, you should know the difference between using a honing rod and actually sharpening the knives. The honing rod is used only to deburr your knife, keeping it sharp. This does not mean it will always stay sharp; it will still go blunt over time. Personally, I prefer to bring my Global knives to a professional sharpener every other year to get them sharpened properly.
I have posted this recently on another question, but a leather strop and some buffing compound will probably be a safer bet then a ceramic (or metal) steel. I have a range of the Global knives and will use the strop in-between whetstone sharpening. The strop & compound only removes a microscopic amount of metal from the knife, and you don't run much risk of damage or changing the shape of the bevel.