Hold Fast Straps

Don't know about the hold-fast but mine have 2 separately adjustable straps so you can get them perfect for every shoe you have. They are fairly grippy on the inside so once your foot is pushed in it is pretty tightly in there. Obviously pulling straight back gets you out like on powergrips and clips/straps.

I think powergrips are limiting as they are fixed at one length. I for one definitely ride in more than one pair of shoes.

If powergrips are set up correctly you shouldn't be able to release by pulling straight back....you're supposed to have to twist out slightly due to them being mounted diagonally.