Matus what do you think about the belt grinder you are currently using, in terms of grinding power, speed and every other aspect of it?
Let me give it a try. First of all - the grinder could indeed use bit more power - 1/2 hp instead of 1/3 would be nice, but it still allows for reasonable material removal. The point is to use high quality belts - I have bet experience with Norton Blaze 60 and 120 and 3M Trizact (normal and 'gator'). The speed is medium - fast enough given the power - can also be used very well to grind handle blocks to shape what is a great plus and saves a lot of time. With handle materials you can not push too hard as otherwise they will burn, so the speed or power is not really an issue there.
Also - when shaping blanks after you have cut them with a hack saw or with a angle grinder (I made eight 180mm petty blanks with angle grinder) the speed with a sharp belt is incomparable to what it would take with a coarse file.
The particular model I have had problems with running stiffer belts - they would roll-off the wheels because the only degree of freedom you have is the angle of the back small wheel and the range was not enough. I used a brute-force approach and bent the whole frame a little. It works not, but the belts are running a few mm off the platen. This could of course be fixed by making a proper platen for the grinder, but I did not bother as I am not grinding plunge lines and I have a 2x72" on order.
I may have spend just 80 on the grinder, but I have spent about 200 on the belts (though I still have a decent stash of them). That is something to keep in mind.
I have ground a few of the 180mm O1 petty blanks, one 180 Niolox gyuto and currently working on three 210 mm gyuto knives - and the grinder keeps working. I would wish for a more speed there as the gyutos are made from 3.0 and 3.5 mm thick stock, so a lot of material needs to be removed. With the 180 mm gyuto which is from 2.2 mm stock it was OK.
In total I would say - if you do invest in a good quality belts than a grinder like this is a very good starting machine to learn grinding and to make some knives and see how you like it before you would get a more powerful and more flexible grinder. The price is worth it. And even should you later get a big 2x72" the narrow 1" belt is practical when shaping handles (with or without platen).
What I dislike about mine is that the work rests are both made from aluminium - I had to put a glossy tape on them otherwise they stain & scratch handle material. But most 1x30" I have seen online seemed to have steel work rests.