In my opinion Novotel is MUCH nicer than Ibis. They are both part of Accor Hotels, where Ibis is the cheaper no frills hotel and Novotel more the business class style hotel which is much more comfortable.

Have stayed at both brands before and IMHO I'd go for Novotel any day and especially if the price is around the same. Only thing I have against Novotel is their blood sucking price on breakfast (on average around EUR 15 per pers)...