My tuppence-worth as I own a 3.6 TDV8 may sound harsh and it't not meant that way at all but it is the reality.
If fuel economy is a concern - don't buy one.
If electrics are a concern - don't buy one.
If Air suspension scares you - don't buy one.
If you don't have about £1500 per year to spend on maintenance - don't buy one.
If it's really cheap or has minimal history - Don't buy that one!
Ok, so that's the bad stuff covered off but the OP has already suggested it's not always about the cost so here's a balanced view (from an imbalanced mind):
I get 19mpg average but these days that is very little motorway driving. On a run as I did last week for about 8 hour of Autoroute at 130kmh (80mph), it managed 28.5 MPG which is good I think. Couple that with the fact that we only go out of the car once for 20 minutes and still arrived fresh I would say it's excellent! The reality is that you are unlikely to break 22mpg over the course of your ownership unless you manage a 4.4 with 8 speed and it might do a little more I'm led to believe.
The L322 is an absolute pleasure to drive and in my opinion far and away better than the Discovery/RR Sport. We have a Disco 4 also and that is as comfortable inside but less compliant as it is a body on frame rather than the Monocoque. My brother had a supercharged RRS and it was epic for distance too even though it was an early one. They are all great cars in their own right.
The inverse of my negativity above is that you need to adjust your thinking around the ownership of these cars, remember that they were £80k new and that the parts are not any cheaper now than they were then, there are aftermarket options but not for everything of course.
Sadly, a lot of them now have had several owners recently who ignore issues and when they mount up the car gets sold and the cycle repeats. They are old and they do go wrong but that's ok, just address each thing as it happens and you won't be too upset. If you're handy with the spanners and you can use a search on the forum or ask the right question with plenty of detail then you'll get loads of help here and on other forums (If you start a post with "Limp Mode on My Range Rover, what is wrong?" you're not going to get far, that's just common sense).
Initially, I found that working on these was daunting which was a first for me but again, not a bid deal once you get used to the size of the hammer you need to wield at a lump this size and also remember that they are very heavy vehicles so you're better off approaching it with HGV fitter mentality and you WILL NEED a big trolley jack and stands that can support the weight.
On the subject of maintenance, I have spent about £300 on mine this week and in the 9 months I've owned it I've spent a total of £2294 on maintenance of which a fair chunk was preventative for completeness though, I bought mine as an auction gamble (cheap) so I expected to spend a lot on it to get it where I wanted it. There is a video on YouTube all about it if you're interested. Also, if you look at it this way £2294/12 is £191.16 per month and that won't buy a very exciting car on a lease deal but you'll actually own the RR and it's a bloody sight more interesting to drive than a Nissan Quashqai!
Good luck with your decision.
P.S. I (ahem) absolutely wouldn't dream of blanking the EGRs let alone have them mapped out that would be a terrible, terrible thing to admit to I mean do. It would be a terrible thing to do! Phew, that was close...