20/250 vision is... really good. Able to use a full 80x24 terminal with ease. Able to drive as long as you're not too picky about legality or reading signs. Able to read facial expressions in a conversation. I'm very curious about the details of 'equivalent'.
Wow, yeah. I'm 20/400ish without my contacts in (nearsighted, -3.75/-4.0, plus some mild astigmatism), and while I couldn't drive a vehicle like that (or rather, wouldn't - I could probably stay in the lane okay during the day, but wouldn't be able to read any signs, and after dark the whole experience would be terrifying), I can certainly interact fine with others, read facial expressions as long as a person isn't on the complete other side of the room, can easily navigate unfamiliar rooms, and use a book or a screen as long as I hold it within a foot of my face.
With nearsightedness, you can have nearly normal vision 1 foot away even if you have much worse vision 20 feet away. With this system I suspect you can see things better when they're closer just because they encompass more of the visual field, but you probably can't see something 1 foot away nearly as well as a myopic person with 20/250 vision.
On the other hand, you might still be able to read. The vOICe people published a paper (http://www.sciencedirect.com/science/article/pii/S0896627312...) that shows that regions of the brain that are activated by letters/words in normal individuals and by Braille reading in the blind are activated by vOICe after training.
It's limited to 1 fps though. However I'm very impressed this is possible. I had a similar idea recently, and had no idea it had already been done or worked so well.