I looked at getting a Saris Bones for my new Astra estate. However I thought they were overpriced tbh. I bought a Thule 9104 from the Roof Box Conpany for £80. It doesn't have any straps as such, just metal strips. It has a tensioning system which locks the whole thing onto your bootlid. A hassle to set up first time but every time after that it is super fast to use.
The rubber blocks can be moved around to fit various bikes. My spesh Pitch goes on fine on the seatstays and top tube, and only needs 1 strap (supplied with rack) to hold it on very securely.
It is honestly the best bike rack I have ever used and I am so impressed with it I am recommending it to everyone! I am the most paranoid person when it comes to putting bikes on cars but I totally trust this one. I prefer it over my full Thule Aerobar roof set up that cost me £220.
If you want to know more then email me on rcatkin@googlemail.com. And, no, I don't work for Thule!!! I am just so pleased with it.