Well since we are on this subject anyway, I have to chime in. Others can use this info.
If your talking about and 'electronic' converter as in a VFD (variable frequency drive) that's a good choice. They do produce 3 phase and a good choice. There is a limit to the size that is practical and I think 5HP is right at that limit.
If your talking about a Static Phase converter, that has it's applications but not a great choice in my mind. They do not provide 3 phase power to the motor. Once you get a 3 phase motor spinning it will run on single phase (2 hot wires vs 3 hot wires). The provide 3 hot legs to get the motor started and then it runs on 2. It can't produce it full power. I read 1/2- 2/3 of the rate HP.
If your going to do several machines a Rotary is the way to go. 3 phase machines are often cheaper and much heavier. A rotary converter fires up a 3 phase motor and the runs on 2 legs, but it uses the the 3 unused leg of the motor as a generator, it generators the 3rd leg of 3 phase. Then you can use the 2 hot wires you have and the 3rd leg your motor generate the 3rd. It works great.
I have a rotary converter and I love it. I can buy 3 phase machines cheaply because others pass them over. I just have to start the phase converter first. No biggie.