I have a portaband at home, and a very nice, heavy Do-All metal cutting bandsaw at work. There is really not a lot of difference between them when it comes to what they're capable of doing. The big machine cuts a little better, bands last longer, but the 1/2" blade width is really the limiting factor of what you can do without resorting to match-stick cutting. The other nice thing about the big machine is speed control, some have band welders, bigger cutting envelope, heavier duty blade guides cut straighter, etc, but honestly unless you are doing something else with a big saw like splitting wood blocks or the like, I don't see it being worth the space it takes up unless you have the space to spare.
I have and use frequently, two lasers at work. They are quite capable of cutting a blank to nearly finished dimension, completely finished in some cases depending on the type of knife, how it's assembled, material used, very quickly and efficiently once set up properly. For example, I could cut a Loveless style blank from say 3/16" A2, with all required holes to finished size, the outside profile to finished size with almost no heat affected zone (using nitrogen rather than oxygen) and have any tabs or notches for guards/bolsters within .005-.010" of final hand fit dimensions, in about 40 seconds of actual cut time. I've toyed with the idea of offering this as a service, however, the time sink comes from developing cut parameters for the steel being cut, receiving the steel from the customer, drawing the DXF file if not provided and even if it's provided checking it for errors/scale issues, and programming it for the steel provided. And it really sucks to be constrained by 2" wide strips of material. There are a lot of issues with narrow material like tipping on the slats of the machine, moving as the part is cut, etc. It's a far more repeatable process with a minimum sheet size of 6x36" which most people don't want to buy. I even considered stocking material but don't want that headache either. So what I'm getting at is that it's roughly a $100/hour machine, and the actual machine time is only $1 per blade, but it's a good 2 or 3 hours of preparation to get 2 or 3 designs of knife onto a single type of steel and running on the laser, whether I cut 1 of each profile or 100 of each. Sans the material expense, the bar napkin quote for 2-3 profiles, one of each from the same material, is $303. The cost for 10 of each (30 blanks) is only $330. 100 total blanks, $400. See what I'm getting at? 3 blanks is $100 each. 100 blanks are $4 each. For the cutting service. I don't know what people charge for this service who do offer it, I'm just posting the calculus I came up with regarding what I could do. Everyone's overhead and cost structure is different. Someone with a less burdened, fully depreciated machine could likely do it for less at the lower quantities than I could. Again, that's spitballing. I don't want to even attempt to deal with 100 different profiles, from different people, every one from a different material grade and thickness. But I would be happy for an opportunity to cut 25 blanks each of 4 different profiles from the same material and thickness.
Water jet I'm less familiar with. It's slower than laser, but can generally achieve a higher cut quality. For knife making purposes, the difference in cut quality is very low impact in my opinion. The chief advantage is that with no heat, there's no heat affected zone, and with no heat, the water jet is capable of making cuts the laser cannot without distorting the material to the point of melting. IE blanks can be placed closer together, webs can have tighter corners/radii. I have no idea what this costs as they're too slow for our(my work) purposes and so I've done very little research on them.
