I used to have one, whilst living up in London - it was the only way I could get insurance and that still came in at £1700!
Anyway, it was paid for and the company came down and built it for me on a concrete plinth. All fine and dandy - bit of a bug bear trying to gett he bike into the front cradle at first, but eventually got the hang of it and it worked really well. In ever feared for the bike whilst in the 'garage' although I always ensured the alarm was also set.
If you aren't planning to ever move, then it is spot on, you can break them down to ship, but they are heavy and you''ll need at least a couple of mates!