We ended up with a BMW AUC 2011 plate 2.0 Xdrive SE auto in Vermillion Red which I quite like - it's like a burgundy sort of colour and a little bit boudoir

Firstly the gearbox is the aforementioned 6 speed auto, not the 8 as in my E70. Very different in how it behaves. Where the 8 sometimes feels like it can't quite make its mind up as to what gear it's in (especially when cold) the 6 plumps for a gear which tends to be on the revvier side and sticks with it much more. Changes aren't as smooth but it feels like a far less fussy unit, for want of a better way of describing it. It's also quite keen to kick down even when warmed up whereas the 8 will sometimes need more of a shove on the throttle for it to realise a change in ratio is needed. However at all other times, for me, the 8 speed unit is far better. Smoother changes, less of a feel like it's "slipping" at times in order to keep you in the power band (more ratios to play with) and I have flappies

The dash is very similar to that in the E70, just like it's been on a hot wash. And I have to say some of the plastics especially lower down (like steering column shroud/ trim) are just plain shoddy. Very hard and cheap feeling. However, despite this none of it creaks, rattles and groans like the E70 interior which has always bugged me for a car of its class. It has nav so an iDrive screen in the middle of the dash however this is smaller than that in the E70 and has a bigger shroud to fill some of the space. Feels like when you used to watch widescreen movies on a normal telly with the black lines, except at either side instead of top and bottom. However it does feel far more responsive than the iDrive in my E70 - not sure why this would be? Less features perhaps (she has no DAB for example)? Definite shortage of cupholders though, with only the one squeezed in on the centre console vs the E70's two.
Oh and get this - it has a proper handbrake. Jealous......

Engine wise it's the 177bhp 2.0d unit which combined with the much reduced weight of the car and 4wd makes it a sprightly little thing off the mark. At higher speeds it feels a bit breathless where the 3.0d would still have some shove, and at times you can tell it needs some more mid range but it's otherwise just fine.
Definitely lacking in refinement with the loss of 2 cylinders, and clearly some sound proofing (and I'm sure the 184bhp unit is smoother) but compared to the bland Audi 140bhp unit it feels like it has some character and is much more willing to rev.
MPG wise it's not bad - I'd say mid 40's. Sure if we'd have got an SDrive it would have been better but this was otherwise the right car and I think my wife likes the extra surefooted-ness of AWD as her previous E87 1 series was a bit twitchy in the wet she said.
In terms of ride, even with 17" * marked Pirelli RFT's it's night and day better than the E70 which crashes and bangs over things the E84 doesn't even notice. It doesn't feel like it has a need to go to non RFT's as these behave just fine. Think the SE suspension is squishy enough (apparently based on the E91 3 series chassis) but the handling is still absolutely superb and the car feels very pointy and level. Combine this with the relatively heavy steering (makes the E70 feel very light when I get back in it) it is great fun to smash down a B road. Less so in town as the steering can almost feel too heavy and I can't palm the wheel round when parking etc like I can the E70. I guess here the massive weight of the E70 is unavoidable so the suspension in the E84 doesn't need to be stiffer than a stiff thing to compensate.
Aside from this, it boils down to the fact that the E70 simply has more toys due to being simply a higher spec car and in my case an LCI. Flappies with 8 speed, leather bum warmers, Xenons, even rear vents (the E84 doesn't have vents pointing at rear passengers.....). You're therefore almost into apples vs oranges territory trying to directly compare them but I've definitely got to say getting into the X1 does put a smile on my face whereas the X5 feels better for lazy wafting.