No, it's not only if you use the factory OS image: http://www.theregister.co.uk/2015/08/12/lenovo_firmware_nast... - it is, indeed, only if you use Windows for now. But there was a time where pressing the "restore" key on the IdeaPad (yes, there was one, that starts a windows restore) would bork a Linux install.

ThinkPad hardware is OK, but it's very hard to trust Lenovo with anything these days. A good summary I found while looking for the above link is http://www.makeuseof.com/tag/now-three-pre-installed-malware...