"Rover direct-injected 'T' Series diesels okay, but only gain about 7 mpg on the petrol 2.0 litre."
What!!! Where did you get those figures from....I have owned 2 Rover 600's, one a 2.0SLI and the other a 2.0 diesel, and I can tell you that I average around 48 mpg with the diesel (I get 56 mpg on a long motorway run), I used to average about 33mpg on the petrol.
To answer the origional post, I have been very pleased with both my 600's
Most of the rust problems mentioned are only a problem on pre 1996 cars. Rover improved rust proofing after '96. Do watch for electric window probelms, especially the drivers one.....the mechanism can wear, causing all sorts of nasty problems. Make sure the electric arial works too....that'll cost you about £60 and an hours worth of fiddly work to get it in.
They take high mileage very well, but if you're going for a Ti, go for the lowest mileage example you can find. (not many low miler Ti's about these days).
In my experience, the 600 has above average reliability.....Certianly better than Peugeot's, Renault's, Vauxhall's, Fiat's and Seat's I've owned, I had a Mazda 626, which was probably as reliable as the 600.
I've done 30,000 miles in mine in 16 months, and I have'nt had to take a spanner anywhere near it....Apart from an oil change or two. When I have put mega miles on it, I shall flog it, and go out and buy my 3rd 600.