I don't think they are similar at all.
IMO Bleu de Chanel was always going to take a pasting from people because people, in general, don't like the "new". It never stood a chance.
It's a shame it's been pre judged by so many as I think it is the best new fragrance Chanel has brought out for men (excluding Edition Blanche because it's a flanker) since................. Egoiste.
Polo Blue is a generic aqua/sports cologne which is very much of it's time. It's not offensive by any means but it's part of that American CK/Ralph Lauren/Tommy Hilfiger thing of the early to mid 90's where it was best to be fresh and sporty.
Im gonna watch Bleu de Chanel..... I think it will be around for a while yet.