I've stayed at both.

Both are good hotels. The Novotel is a bit more upscale (not by much). There are some small rooms at the Ibis, but I got a very large one, for some reason.

I had a lot of problems getting a modem connection at the Ibis. There is an internet terminal downstairs.

The Novotel has a full-service restuarant, I think the Ibis is breakfast only. But there are so many places to eat around there, it hardly matters.