This is an excellent piece of kit. I have been using it for just over a year and have transferred it between several different cars several times a week.
I bought it initially as my Volvo V70 didn't have a long enough seat belt to fit the maxi cosi cabriofix properly but this did the trick as it requires a shorter seat belt to attach.
It literally takes a minute or two to fix into place after you have got the hang of it and it ensures that the car seat is always solid and also easy to remove the seat if baby is sleeping to carry them inside.
The only word of caution is that it is reasonably heavy as it solid metal although fine to carry for short distances between cars. On the other side this gives peace of mind as you know the car seat if attached securely.
It has clear colour indicators to show when it is fitted properly so you can't get it wrong. Well worth the money. So far this has been used in a Volvo V70, Volvo S60, Honda Civic and VW Passat with no problems (None of the cars had isofix, all attached via the seat belt). I am sure it would fit a smaller car although the seat in front may need to be put slightly further forward to accommodate the leg at the front.