Stayed @ Marriott Heidelberg in 2012. Close to the railway Station but too far away to the origin Heidelberg. The Lounge in the 3rd floor is cool. You can watch People rowing on the Neckar :-)
Somewhat of a far walk from many of the attractions in Heidelberg. It would be best to take a taxi. About a couple minute taxi ride from the train station.
I agree about the beautiful view out of the executive lounge ... But everything else is far below their usual lounge standards ... The food choice is poor and the breakfast is tasteless - 2/10
Heidelberg Marriott Hotel is set in a picturesque, riverfront location and offers well-appointed hotel rooms and suites with deluxe bedding and thoughtful amenities. Hotel perks include two restaurants, elegant event venues, a gym and an indoor pool.