we are considering getting one but i am happy with the one we have now
how do they compare speed wise etc

The X5 is only of any use if you are in real need of space, or live in the country where 4x4 is a must.
You,ll find that the BMW 5 series tourer is probably much closer to what your looking for & need from your vehicle.
They have a Euro n-cap 5 star rating for safety which is better than the X5.
In my opinion, the new Renault Laguna 3.0 litre tourer is probably the best family car in production at the moment. Check out Renault UKs website and you,ll see what I mean.

You'd be moving from a sports saloon to a lumbering great 4X4. The speed may not be too different but the handling is - try going round a corner at high speed in an X5 and then try and guess why the scenery is upside down or why you're facing oncoming traffic! My brother went from a 5 series to an X5 and he'd sold it within a year and got a Range Rover Sport instead - he hated it.

Personally I'm an Audi man, so I wouldn't have either.

if you want to go offroad no but otherwise yes

if you are happy stay with it.....