Zippity:BiggusDoggus: It wouldn't be a very attractive option anyway - it would take over 3 years of rentals to make up the $599, and you'd be responsible for any repairs etc.
How about arguing with real facts and not just the chip on your shoulders :(
1/ I was basing my comments on the "facts" provided by Sky.
2/ And besides, what kind of warranty period does the box have if you buy it outright? As in, if it blows up within the first 40 months (40 x $15 = $599 (ish) will they replace it free of charge? If so, then all good I suppose.