Very well built but the bad bit is very heavy on fuel otherwise has every extra available.
The 7 series BMW are heavy on fuel, even the diesels. The build quality is good, they are comfortable and the handling is good too. Reliability is good as long as they are serviced properly but if they go wrong then expect a huge bill.
I bought this car specifially to cope with a couple of years of occasional motorway driving as a cheap altenative to using a hire car. Afrer doing 38000 mile in 2 years its averaged 32.8 mpg which is good for a car of this size. Its interior is luxurious and the engine cruises sweetly on the motorway. Its been very reliable and my guess is the engine will outlive the running gear etc. When they were built I alwys considered them less good looking than the equivalent Jaguar or Mercedes. Now afer time I prefer the BMW.
My partner and I had heard about the depreciation on the 7 Series many years ago now, and hatched an evil plan to buy one when it had got really cheap. It was only half an idea really, but as it happened when we were car shopping a few years ago we saw one that looked in good nick, and it was either that or some newer but much more boring car. So we decided to give it a whirl, and were not disappointed!! They're even cheaper nowadays, you could probably pick one up for less than a few thousand, which is silly money when you consider what you're getting. It might only last a year or so, but what a year!
So what impressed us was that the BMW 730i was big but small, felt agile and punchy despite its massive size, and for all that was relatively easy to move around, and park etc., yes yes even for a girl. It's lovely and comfy, much better than the newer Fords and Vauxhalls we were looking at in the same price bracket.
I'm not a big car person and I'm not bothered about driving all that fast, but what does make me literally whoop sometimes is the ability to overtake in more or less any old gap in the traffic. I love it, and I'll find it very difficult to go back to a more boring car if I have to. Anyway all this isn't to say that it's not safe to take the kids around in. It feels very well built, and the service hasn't spotted any major rust or body deterioration.
There are a few wobbles here and there, but understandable for its age, like needing a new timing chain a year ago, and just recently a new fuel pump. It also has a slow oil leak which I suppose won't be realistically fixable, but then for a car with 190 thousand miles it's doing very well.
The BMW 730i is a good family car in other ways too. The boot is just huge, easily big enough for all the various trips and holidays we've flung into it, and we're not careful packing things in either. One down side against the cheaper/modern cars is that they haven't put in all that many sort of cup holders and things that you might expect, which gets a little tiresome when the kids have got drinks and things back there, but we just tend to give them bottled drinks that can bounce around the car if need be.
I don't know how much longer our 7 Series will last but however long it is, I'll seriously be considering another one. Having said that, I know that BMW parts are probably pretty expensive, so it might have quite an expensive end of its life. That might change my mind!