Always used their stuff and yes, its as easy as claimed. Take your time, plan it, have the tools to hand and, certainly if you're going for any larger stickers, have somebody around to help as required.
As for removal, again, take your time. Use a hair dryer or heat gun on low power to gently warm the sticker as your assistant slowly peels it off, the sharper the 'peeling angle' the better. Never suffered any damage and there's not even much, if any, residue once the sticker has gone.
Good quality products which work as you'd hope and expect.