Brilliant commentary on that video!

I'm planning on getting servos when I make the new gantry for my router since it will be too heavy for steppers to be economical. Recently I contacted the following supplier in China and they are the cheapest place I have found so far:

Find All China Products On Sale from Hangzhou Mige Electric Co., Ltd. on Aliexpress.com - 2 sets of 750 watts AC servo motor kits and 1 set 750W servo motor drive with brake with 6 sets 10 meters cables,2 sets 400w ac servo kit and 1 set 750w servo k

She quoted:

750w servo motor cost US$145 EXW per piece
600w servo motor cost Us$140 EXW per piece
740w and 600w use the same model driver
SDB08NK0 driver cost US$230 EXW per piece
per set (motor and driver) include 3 meters cables and connectors free of charge

That's not including shipping, so I asked for the price for 3 of the 750W motors and drivers with 6m cables and shipping was $120 so $1245 total, which is £260 per motor/driver pair. They run directly from the mains, so that's everything you need.

Also at the end of this year they can supply the motors with 17-bit encoders, which would be brilliant for a 4th axis. That does however add $80 to the cost of the driver and $80 to the motor. It's going to be a long long time until I can afford to get anything like this, but I'm researching now so I know what is the best option when the time comes. I'm also thinking of getting one of the larger motors, around 2kW, for my lathe to do something like in the video you linked to...

Another option is DMM servos in the USA.

Which stepper and driver did you try?