Alow me to offer up my opinion...my 2002 Disco II has been quite reliable - no issues - I haven't had it for very long (about a year - bought used with 55K miles), but understand if your intent is to take it offroad everyday, you cannot expect it to be as reliable as highway driving everyday. I, for one, do not offroad, because this is my primary vehicle.
Many of the issues outlined on this site are from pretty ******** offroaders. I would bet the farm that the "Highway Rovers" are not as problematic. Offroading puts some major strain on engine, and suspension, and also could manifest other problems in areas you wouldn't expect. I think Rovers get a bad rap because they take some monster abuse...not that they are nessessarily unreliable - so maybe it's not as reliable as a Toyota 4-Runner, but definitely better than a Pontiac Fiero (don't get me started).
Also, driving and maintaining the car properly - using good gas (I put in premium all the time), using Mobil One Synthetic Oil, and fixing any issue as soon as I am able - also helps reliability. I remember my sister whining about how here Prelude was not a good car. She drove over 29K miles before she relaized she had to change the oil... It forever affected her Prelude (but it still ran for 225K miles)....
Now also, I am very prepared and capable of fixing quite a few things myself (brakes, change oil, replace lamps and simple switches, troubleshoot electronics, etc), and I am not one to immediately run to the Stealership at the onset of any issues...I will first make an attempt to fix myself, and only when I am not able to fix it would I consider going to the Stealership.
My 2 cents